Wheel bearing with sensor

Abstract

A bearing arrangement of a wheel mount for the rotatable mounting of a vehicle wheel relative to a vehicle body, which includes: - an outer element (1) with an inner perimeter formed with a plurality of rolling surfaces (3, 4); - an inner element (2) with an outer perimeter formed with rolling surfaces (3, 4) which are held in an opposite relationship to the rolling surfaces (3, 4) described above; - a plurality of rows of rolling elements (5) arranged between the rolling surface (3) of the outer element (1) and the rolling surface (4) of the inner element (2); - a body connection flange (1a) to be attached to a steering knuckle provided on an outer circumference of the outer element; and - one or more sensor units (20, 20a, 20d) comprising a strain-generating element (21) with two or more contact attachment segments (21a) adapted for attachment to the outer circumference of the outer element (1) by contact therewith, and a sensor attached to the strain-generating element (21) and functional to detect a strain induced in the strain-generating element (21) at an arcuate section (1aa) designed to extend from a bottom end of an outwardly facing side surface of the flange to the outer circumference of the outer element (1), or at an outer circumferential surface area of ​​the outer element (1) adjacent to the arcuate section (1aa) on an outer side,wherein the flange has a front highlighted form of line symmetry with respect to a line segment perpendicular to a bearing axis or a point of symmetry above the bearing axis, - wherein the one or more sensor units (20, 20a, 20d) are surrounded by a tubular protective plate (29) with an edge element (35) made of an elastic material, which surrounds an outer circumference of the outer element (1).

Description

Background of the invention (field of invention)

[0001] The present invention relates to a sensor-equipped bearing assembly for a wheel support having a load sensor built therein for detecting a load acting on a bearing unit of a vehicle wheel. (Description of the state of the art)

[0002] As a technique for detecting a load acting on one of the vehicle wheels of an automobile, a sensor-equipped wheel support bearing assembly has been proposed, for example, in Patent Document 1 below, in which the detection is carried out on strains occurring in a flange portion of the outer diametrical surface of an outer ring (an outer member) of the wheel support bearing assembly, which forms a stationary ring. In addition, such a wheel support bearing assembly as in Fig. 43, for example, as proposed in Patent Document 2 below, in which a strain gauge 51 is adhered to an outer ring 50 of the bearing assembly of a wheel support for the purpose of detecting strains.

[0003] Nevertheless, the inventors of the present invention have proposed a sensor-equipped wheel support bearing assembly having a structure in which a sensor unit including a strain generating element and a strain sensor attached to this strain generating element is attached to a stationary ring of the bearing assembly. The strain generating element has at least two contact-fixing segments with respect to the stationary ring and also has at least one cutout portion defined between the adjacent contact-fixing elements with the strain sensor disposed in this cutout portion. For example, see Patent Document 3 cited below.

[0004] According to the sensor-equipped wheel support bearing assembly disclosed in Patent Document 3 below, when a load is applied to a rotating ring and then a rotating disturbance occurs in the motion of the vehicle, the stationary ring is deformed by the rolling elements, and such deformation leads to strain induced in the sensor unit. The strain sensor provided in the sensor unit detects the strain induced in the sensor unit. If a relationship between the strain and the load is previously determined through a series of experiments and / or simulations, the load applied to a vehicle wheel can be detected, for example, by an output signal of the strain sensor.

[0005] Further bearing arrangements equipped with a sensor are described in the documents DE 11 2007 000 943 T5 and US 2009 / 0 199 660 A1. (State of the art) [Patent Document 1] Published Japanese Patent Application No. 2002-098138 [Patent Document 2] Published Japanese Patent Application No. 2003-530565 [Patent Document 3] Published Japanese Patent Application No. 2007-057299 Summary of the invention

[0006] According to the technique disclosed in the above-mentioned Patent Document 1, strain generated as a result of deformation of a flange portion of the stationary ring is detected. However, with such an involved problem, it has been found that when the deformation of the flange portion of the stationary ring is accompanied by slippage, in the case of a force exceeding the static friction force between a flange surface and a knuckle, repeated application of the load may result in the formation of hysteresis in an output signal.

[0007] On the other hand, according to the sensor-equipped wheel support bearing assembly disclosed in the above-mentioned Patent Document 2, when the structure is adopted in which the strain gauge 51 is provided on the outer ring 50 of the wheel support bearing assembly as shown in Fig. 43, the sensor cannot be protected from the external environment. Therefore, there is a possibility that pebbles, for example, thrown during the movement of the vehicle, will strike the sensor, thus impairing the sensor, or the sensor may become wet with muddy salt water to such an extent that it will corrode the sensor. Furthermore, there is a problem with mounting.

[0008] In order to avoid the aforementioned problems and inconveniences inherent in the above-discussed prior art wheel support bearing arrangements, the inventors of the present invention have developed the respective structures as shown in the Fig. 44 and Fig. 46. ​​In particular, in the bearing arrangement of a wheel support equipped with a sensor of the type shown in Fig. 44, an annular sensor assembly 54 made of electronic component parts including a plurality of sensor units 53 for the purpose of load detection, a signal processing IC for processing an output signal from each of these sensor units 53 and a signal line for deriving the processed output signals from the respective sensor units 53 to the outside of the bearing assembly, wherein the electronic component parts are arranged within an annular protective plate 52, coaxially attached to an outer peripheral surface of, for example, an outer ring 56 which forms a stationary element of the bearing assembly of a wheel support, by means of a sealing element 55.

[0009] On the other hand, in the bearing arrangement of a wheel support equipped with a sensor, the Fig. 46, the electronic component parts which are incorporated in the bearing assembly of a wheel support of the vehicle shown in Fig. 44 are applied, are connected together in a ring shape to complete a sensor assembly 64, which in turn is fitted in a coaxial relationship to, for example, an outer ring 65 constituting a stationary member of the bearing assembly of a wheel support, fixed to an outer peripheral surface of the outer ring 65, and is also covered with a tubular shroud 62 having a shape whose inner diameter increases toward an inboard side, whose inboard end portion is fitted to the outer peripheral surface of the outer ring 65, whereas an outboard end portion of the shroud 62 is fitted to the outer peripheral surface of the outer ring 65 by means of a sealing member 66 made of an elastic material.

[0010] The Fig. 44 shown and with reference to the Fig. 44 has a problem of sealability, mountability and cost, since the sensor assembly 54 has a complicated shape and since the guard plate 52 is generally made of two separate elements which are connected to each other by a hinge 57 as in the Fig. 45A and Fig. 45B are connected to each other.

[0011] The Fig. 46 and described with reference thereto has a problem in assemblability and cost because the sealing member 66, which is a separate member from the shroud 62, must engage in a groove defined in the outer peripheral surface of the outer ring 65 constituting the stationary member.

[0012] In the sensor-equipped wheel support bearing assembly disclosed in the above-mentioned Patent Document 3, a problem has been found that since the stationary ring on which the sensor unit is mounted is an outer ring of the wheel support bearing assembly of, for example, the third generation, and since a knuckle mounting flange of such an outer ring has a complicated shape, the output of the sensor unit tends to have a detection error influenced by its complicated shape.

[0013] More specifically, the aforementioned outer ring flange has bolt insertion holes or overflow holes defined therein for securing the corresponding bolts to a steering knuckle. However, in order to reduce weight, these bolt insertion holes or overflow holes are generally designed to have a varying diameter over the entire circumference of each hole, and instead, have a protrusion at a certain circumferential portion of each bolt insertion hole or overflow hole, while the remaining circumferential portion of each bolt insertion hole or overflow hole is generally designed to present a petal shape when viewed from the front, limited by a non-protrusion portion or a portion of minimum protrusion length.Accordingly, in the case where expansion-contraction strain other than stress occurs as a result of temperature rise or cooling during use of the bearing assembly, the magnitude of expansion-contraction and temperature distribution of various parts of the outer ring will no longer be uniform due to the complicated shape of the outer ring flange as discussed hereinbefore, and, if the sensor unit is attached to an irregular side, influences caused by the magnitude of expansion-contraction or temperature distribution of a detection signal will occur, and therefore it will become difficult for the method to cancel such influences.For example, in the outer ring of the type as mentioned above, if the sensor unit is arranged at a relatively highly stable region in which even if a stress having a uniform height occurs, the strain amount will be small, so that the amount of strain change is also small in such a region affected by a stress influence, and therefore the sensor unit tends to output the detection signal with a large error.

[0014] The first aspect of the present invention is to provide a sensor-equipped wheel support bearing assembly of the type in which the detection error resulting from the shape of the outer member is reduced to enable accurate estimation of the load acting on the vehicle wheel.

[0015] The second aspect of the present invention is to provide a sensor-equipped wheel support bearing assembly of the type in which the load acting on the wheel support bearing assembly or a tire contact ground area can be accurately detected for a longer period of time while preventing any problems occurring in the sensor due to the action of an influence caused by an external environment, and in which wiring processes of signal lines and sensor assemblies, fitting of a fender and other sealing members can be enabled at reduced costs.

[0016] These aspects are solved by the bearing assembly having the features of claim 1. Embodiments thereof are specified in the dependent claims. The first sensor-equipped wheel support bearing assembly of the present invention is a wheel support bearing assembly for rotatably supporting a vehicle wheel with respect to a vehicle body, comprising an outer member having an inner periphery formed with a plurality of rolling surfaces, an inner member having an outer periphery formed with rolling surfaces held in opposing relationship with the above-described rolling surfaces, a plurality of rows of rolling elements disposed between the rolling surface of the outer member and the rolling surface of the inner member, a vehicle body connecting flange to be fixed to a steering knuckle provided on an outer periphery of the outer member;and one or more sensor units including a strain generating element having two or more contact fixing segments adapted to be fixed to the outer periphery of the outer member in contact therewith, and a sensor adapted to the strain generating element and operable to detect a strain induced in the strain generating element provided at an arcuate portion formed to lead from a bottom end of an outwardly facing side surface of the flange toward the outer periphery of the outer member, or at an outer peripheral surface portion of the outer member adjacent to the arcuate portion portion on an outer side;wherein the flange has a front highlighted shape with a line symmetry with respect to a line segment perpendicular to a bearing axis or a point symmetry about the bearing axis, wherein the one or more sensor units are surrounded by a tubular guard with a rim member made of an elastic material surrounding an outer periphery of the outer member;

[0017] In one embodiment of the present invention, each of the one or more sensor units may be provided at a position in which a line segment including a center of each of the rolling elements on the outer side and defining a contact angle of the rolling elements crosses the outer circumference of the outer member or a position adjacent thereto.

[0018] The above-mentioned sensor unit is used in a plurality, and these sensor units are preferably provided at an equal pitch in a circumferential direction on the outer periphery of the outer member.

[0019] In the above-described structure, when a load is applied between the wheel tire and the road surface, the load is also applied to the outer member of the bearing assembly of a wheel support, resulting in deformation. In the present invention, since the two or more contact-mounting segments of the strain-generating element in the sensor unit are fixed to the outer periphery of the outer member in contact therewith, the strain induced in the outer member is easily transmitted to the strain-generating element after it is amplified, and such strain is detected with high sensitivity.In particular, since, as described above, the front flange's prominent shape exhibits line symmetry with respect to a line segment perpendicular to a bearing axis or point symmetry above the bearing axis, the shape of the outer member is simplified, and the temperature distribution resulting from complications in the outer member's shape and changes in the expansion-contraction amount can be reduced. Accordingly, by sufficiently reducing the influences caused by changes in the expansion-contraction amount and the temperature distribution in the outer member, the sensor unit is capable of detecting the amount of strain induced by the load.

[0020] Also, in addition to the above-described simplification of the shape of the outer member, the strain on the installation side of the sensor unit becomes large, particularly when the sensor unit is provided on the arcuate portion of the flange formed in the outer periphery of the outer member to extend from a base end of a side of the flange oriented toward the outer side toward the outer periphery of the outer member or the outer peripheral surface area adjacent to the arcuate portion on the outer side, even if the temperature distribution of the outer ring and the change in the expansion-contraction amount occur, their influence can be minimized to enable the sensor unit to detect the strain caused by the load.Accordingly, the load applied to a vehicle wheel can be accurately determined by reducing the detection error resulting from the shape of the outer element.

[0021] Also, in addition to the above-described simplification of the shape of the outer member, the sensor unit is provided at respective positions crossing the line segment, the line segment extending through the center of each of the rolling elements on the outboard side in the direction required to form the contact angle of the rolling element, or extending through respective positions adjacent to these crossing positions, whereby the strain induced at the sides of the sensor unit installation becomes large, and even if the temperature distribution of the outer member and the change in the expansion-contraction amount occur, their influence can be minimized to enable the sensor unit to detect the strain induced by the load. Accordingly, the load imposed on the vehicle wheel can be accurately determined by reducing the detection error resulting from the shape of the outer member.

[0022] In one embodiment of the present invention, the sensor unit may be provided in an outer peripheral surface region of the outer member within a range spaced 5 mm from a terminating end of the arcuate portion region in the outwardly oriented side surface of the flange.When the sensor unit is provided in the outer peripheral surface region of the outer member adjacent to the outer side of the arcuate portion portion, the arcuate portion portion being formed to extend from the base end of the outwardly facing side surface of the flange to the outer periphery of the outer member, provided that it is within the range spaced by 5 mm from the terminating end of the arcuate portion portion in the outwardly facing side surface of the flange as described above, when the temperature change and the change in the expansion-contraction amount slightly occur, the induced influence can be sufficiently reduced to enable the sensor unit to detect the amount of strain induced by the load.

[0023] In one embodiment of the present invention, an outboard end of the fender may be fixed to the outer peripheral surface of the outer member, in which case the edge member provided along an open edge of an inboard end of the flange is held in contact with the outwardly oriented side surface of the flange or the outer peripheral surface of the outer member.

[0024] According to the above-described construction, a plurality of load detection sensor units are provided on the outer peripheral surface of the outer member, and these sensor units are covered with the annular fender. Since the rim member made of an annular elastic member and provided along an open edge of an inner end of the flange is held in contact with the outwardly facing side surface of the flange or the outer peripheral surface of the outer member, the sensor units can be covered with the fender, and by preventing problems arising in the sensor under the influence of the external environment, the load acting on the bearing assembly of a wheel support or the ground surface of the wheel tires can be accurately detected over a longer period of time.For example, the sensor units can be reliably protected from pebbles, muddy water, and / or salt water hitting the outside. Furthermore, the wiring of the signal cable and the assembly of the sensor units are easy to accomplish, and costs can be reduced. Although the protective plate is adapted to the outer peripheral surface of the outer element, the protective plate can be manufactured in such a way that it fits easily, and protection of the sensor units by means of the protective plate is also easily achieved.

[0025] In one embodiment of the present invention, an inner end of the fender may be fixed on the outer peripheral surface of the outer member, in which case the edge member provided along an open edge of an outer end of the flange is held in contact with the outer peripheral surface of the outer member or a surface of the inner member.

[0026] According to the above-described construction, the plurality of sensor units for detecting the load are provided, which are fixed to the outer peripheral surface of the outer member, and these many sensor units are covered with the tube-shaped protective plate.Since the fender has an inboard end secured to an outer diametrical surface of the flange of the outer member, and the rim member made of an annular elastic member provided along an open edge of an inboard end of the flange is held in contact with the outwardly facing side surface of the flange or the outer peripheral surface of the outer member, the sensor units can be covered with the fender, and by avoiding problems arising in the sensor under the influence of the external environment, the load acting on the bearing assembly of a wheel support or the ground surface of the wheel tire can be accurately detected over a longer period of time. For example, the sensor units can be securely protected from pebbles and muddy water impacting from the outside and / or salt water impacting from the outside.

[0027] Also, the wiring of the signal cable and the assembly of the sensor units are easy to accomplish, and costs can be reduced. Since the fender is fitted with its inner end to the outer diametrical surface of the flange of the outer member, installation of the fender is easy. Furthermore, the edge member held in contact with the outer peripheral surface of the outer member is integrally fitted to the fender, so there is no need for, for example, fitting a sealing member. A sealing member encompassing the edge member can be fitted after fitting to the fender, thus facilitating fitting of the sealing member.In addition, although the fender is adapted to the outer circumference of the outer member, in such a case, the fender can be made for further easy adaptation and protection of the sensor units by means of the fender is also easily achieved.

[0028] A sensor assembly may be provided that is fitted to the outer peripheral surface of the outer member in a coaxial manner with the outer member and is surrounded by the protective cover. The sensor assembly comprises electronic component parts including the sensor unit, a signal processing IC for processing an output signal from this sensor unit, and a signal cable for outputting the processed output signal to the outside of a bearing unit, the parts being connected in a ring shape. In the case of such a construction, the sensor assembly of the type in which the electronic component parts including the sensor unit are connected in the ring shape may be covered with the protective cover.

[0029] In one embodiment of the present invention, the sensor unit may be adapted to a flexible substrate, in which case a sensor assembly comprising electronic component parts including the sensor unit, a signal processing IC for processing an output signal of this sensor unit, and a signal cable for outputting the processed output signal to the outside of a bearing unit, the parts being connected in a ring shape, the signal processing IC and the signal cable being adapted to the flexible substrate, is adapted to the outer peripheral surface of the outer member in a coaxial manner with the outer member, and is surrounded by the protective sheet. When the sensor unit is adapted to the flexible substrate as described above, adaptation of the sensor unit is facilitated.Also, adapting the sensor unit, the signal processing IC, and the signal cable to the flexible substrate facilitates connection between the sensor unit, the signal processing IC, and the signal cable by forming a pattern of a circuit on the flexible substrate.

[0030] In one embodiment of the present invention, the outer end of the guard plate may be extended beyond the outer member toward the outer side and may further include a non-contact sealing gap formed between its outer end and the inner member. With this construction, the seal between the guard plate and the outer member is also ensured on the outer side, and therefore, load detection can be achieved accurately, further ensuring that the occurrence of undesirable problems due to environmental influences is avoided.

[0031] In one embodiment of the present invention, the edge element can have a shape that widens outward toward the inner side. With this design, unwanted penetration of muddy water and / or salt water from the inner end into the mudguard can be reliably prevented.

[0032] In one embodiment of the present invention, the edge element may have a shape that tapers diametrically toward the outer side and is held in contact with the outer peripheral surface of the outer element. This design reliably prevents unwanted ingress of muddy water and / or salt water from the outer end into the fender.

[0033] In one embodiment of the present invention, the above-mentioned edge member may have a portion extending within a portion of the outer peripheral surface of the fender to define a covering portion of the outer peripheral surface of the panel. The above-mentioned covering portion of the outer peripheral surface of the panel, with the edge member fitted to the outer peripheral surface of the fender, is provided to extend further toward the inner side beyond the portion in which it is positioned on the fender to ensure the required fitting strength.In the case of this construction, at the outer end of the outer peripheral surface of the fender, a wall comprising the covering portion of the outer peripheral surface of the sheet projects radially outward, and in the presence of this wall, an undesirable flow of muddy water and / or salt water into a portion in which the edge member is held in contact with the outer peripheral surface of the outer member can be prevented to surely prevent undesirable intrusion of the muddy water and / or salt water into the fender.

[0034] In one embodiment of the present invention, the inner member may include a hub flange for securing a vehicle wheel, and the rim member is held in contact with the inwardly facing side surface of this hub flange. In this design, since a seal is achieved between the hub flange of the rotating member and the outboard end of the mudguard, unwanted ingress of muddy water and / or salt water into the mudguard is reliably prevented.

[0035] In one embodiment of the present invention, the sensor units may be four, in which case the four sensor units are arranged at equal intervals on the upper, lower, left, and right surface areas of the outer peripheral surface of the outer member, occupying upper, lower, left, and right positions with respect to the tire-to-ground contact at a phase difference of 90° in a circumferential direction. With this design, the load can be accurately determined under any loading condition.In other words, when the load increases in a certain direction, a region in which the rolling elements contact the rolling surfaces and a region in which the rolling elements do not contact the rolling surface appear with a phase difference of 180°, and therefore, if, in keeping this direction, the sensor units are positioned spaced apart with a phase difference of 180 degrees, the load applied to the outer member by the rolling elements can be transmitted to each of the sensor units, and this load can be detected by the sensor.

[0036] In one embodiment of the present invention, the sensor unit may comprise three or more contact fixing segments and two sensors, the two sensors being respectively fitted between the adjacent first and second contact fixing segments and between the adjacent second and third contact fixing segments, in which case the distance between the adjacent contact fixing segment or the adjacent sensors in the circumferential direction of the outer member is selected to be (1 / 2+n), where n represents an integer, in which case a load is calculated as the sum of the respective output signals of the two sensors used as an average value.In this design, the respective output signals of the two sensors have a phase difference of approximately 180° with respect to each other, and therefore their average represents a value from which a variable component resulting from the passage of the rolling elements has been subtracted. Given this, the load estimation using the average becomes even more accurate. Short description of the drawings

[0037] In any event, the present invention will become more fully understood from the following description of the embodiments, taking into account the accompanying drawings. However, the embodiments and the drawings are intended for purposes of illustration and explanation only and are not intended to limit the scope of the present invention in any way, which scope is determined by the appended claims. In the accompanying drawings, reference numerals are used to designate similar parts in different views, and: Fig. 1 is a diagram illustrating a longitudinal cross-sectional view of a sensor-equipped bearing assembly of a wheel support constructed according to a first embodiment of the present invention, together with a block diagram of a conceptual structure of a detection system used therein; Fig. 2 is an elevational view of an outer ring used in the sensor-equipped wheel support bearing assembly, viewed from an outboard side; Fig. 3 is an enlarged plan view of a sensor unit used in the sensor-equipped bearing assembly of a wheel support; Fig. 4 is a cross-sectional view along the line IV-IV in Fig. 3; Fig. 5 is a sectional view showing another example of installation of a sensor unit; Fig. 6A is an explanatory diagram showing how influences caused by the positions of the rolling elements affect an output signal of the sensor unit; Fig. 6B is an explanatory diagram showing how influences caused by the positions of the rolling elements affect an output signal of the sensor unit; Fig. 6C is an explanatory diagram showing how influences caused by the positions of the rolling elements affect an output signal of the sensor units; Fig. 7 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a second embodiment of the present invention; Fig. 8 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a third embodiment of the present invention; Fig. 9 is an enhanced front view of the outer ring of the sensor-equipped wheel support bearing assembly viewed from the outboard side; Fig. 10 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a fourth embodiment of the present invention; Fig. 11 is a highlighted front view of the outer ring of the sensor-equipped bearing assembly of a wheel support as viewed from the outboard side; Fig. 12 is a fragmentary enlarged sectional view of a portion of the Fig. 10; Fig. 13 is a cross-sectional view taken along line XIII-XIII in Fig. 11; Fig. 14 is an enlarged plan view of the sensor unit used in the sensor-equipped wheel support bearing assembly; Fig. 15 is a cross-sectional view taken along the line XV-XV in Fig. 14; Fig. 16A is a developed plan view showing an example of an arrangement of electronic component parts arranged in a sensor assembly; Fig. 16B is a cross-sectional view taken along line XVIb-XVIb in Fig. 16A; Fig. 17A is a developed plan view showing another example of an arrangement of electronic component parts arranged in the sensor assembly; Fig. 17B is a sectional view of the Fig. 17A; Fig. 18A is a developed plan view showing another example of an arrangement of electronic component parts arranged in the sensor assembly; Fig. 18B is a sectional view of the Fig. 18A; Fig. 19A is a developed plan view showing still another example of an arrangement of electronic component parts arranged in the sensor assembly; Fig. 19B is a sectional view of the Fig. 19A; Fig. 20A is an explanatory diagram showing how the influences caused by the positions of the rolling elements affect the output signal of the sensor unit; Fig. Fig. 20B is an explanatory diagram showing how the influences caused by the positions of the rolling elements affect the output signal of the sensor unit; Fig. 20C is an explanatory diagram showing how the influences caused by the positions of the rolling elements affect the output signal of the sensor unit; Fig. 21 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a fifth embodiment of the present invention; Fig. 22 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a sixth embodiment of the present invention; Fig. 23 is a fragmentary enlarged sectional view of the sensor-equipped bearing assembly of a wheel support; Fig. 24 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support according to a seventh embodiment of the present invention; Fig. 25 is a fragmentary enlarged sectional view of the sensor-equipped bearing assembly of a wheel support; Fig. 26 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support according to an eighth embodiment of the present invention; Fig. 27 is a fragmentary enlarged sectional view of the sensor-equipped bearing assembly of a wheel support; Fig. 28 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a ninth embodiment of the present invention; Fig. 29 is a fragmentary sectional view of the sensor-equipped bearing assembly of a wheel support; Fig. 30 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a tenth embodiment of the present invention; Fig. 31 is an enhanced front view of the outer ring of the sensor-equipped wheel support bearing assembly as viewed from the outboard side; Fig. 32 is a fragmentary enlarged view of a portion of the Fig. 30; Fig. 33 is a cross-sectional view taken along the line XXXIII-XXXIII in Fig. 31; Fig. 34 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to an eleventh embodiment of the present invention; Fig. 35 is a fragmentary enlarged sectional view of the sensor-equipped bearing assembly of a wheel support; Fig. 36 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a twelfth embodiment of the present invention; Fig. 37 is a fragmentary enlarged sectional view of the sensor-equipped bearing assembly of a wheel support; Fig. 38 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a 13th embodiment of the present invention; Fig. 39 is a fragmentary enlarged sectional view of the sensor-equipped bearing assembly of a wheel support; Fig. 40 is a longitudinal sectional view of the sensor-equipped bearing assembly of a wheel support constructed according to a 14th embodiment of the present invention; Fig. 41 is a fragmentary enlarged sectional view of the sensor-equipped bearing assembly of a wheel support; Fig. 42 is a sectional view showing a general overview of a bearing arrangement of a wheel support with a motor built into the wheel, which drives the Fig. 30 bearing assembly of a wheel support equipped with a sensor is used; Fig. 43 is a perspective view showing a conventional example; Fig. 44 is a sectional view showing the proposed example; Fig. 45A is an explanatory diagram used for explaining a fender applied in the proposed example; Fig. 45B is an explanatory diagram used for explaining a fender used in the proposed example; and Fig. 46 is a sectional view showing another conventional example. Description of the preferred embodiments

[0038] A first embodiment of the present invention will be described in detail with reference to the Fig. 1 to Fig. 6A to 6C. The Fig. 1 to Fig. The embodiment shown in Figures 6A to 6C is a third-generation type rotating inner ring model and is applied to a bearing assembly of a wheel support for supporting a driving wheel. Note that in the above and following descriptions, the terms "outboard" and "inboard" are respectively understood to mean one side of the body away from the longitudinal center of the body and the other side of the body close to the longitudinal center of the body after installation in the body.

[0039] A bearing unit in this wheel support bearing arrangement equipped with a sensor contains, as shown in an elongated cut-out view in Fig. 1, an outer ring 1 forming an outer member having an inner periphery formed with a plurality of rolling surfaces 3, an inner member 2 having an outer periphery formed with rolling surfaces 4 defined in an opposed relationship with respect to the rolling surfaces 3, and a plurality of rows of rolling elements 5 disposed between the rolling surfaces 3 of the outer ring 1 and the rolling surfaces 4 of the inner member 2. This wheel support bearing assembly is in the form of a double-row angular contact ball bearing in which the rolling elements 5 are in the form of balls and are held by a retainer by means of a retainer 6 applied to each of the rows. The rolling surfaces 3 and 4 each have arcuate shapes in sections and are formed to enable the contact angles of the respective balls to be maintained in a continuous relationship with each other.Opposite ends of a bearing space defined between the outer ring 1 and the inner element 2 are sealed by the respective sealing elements 7 and 8.

[0040] The outer ring 1 serves as a stationary member and has an outer periphery formed with a body mounting flange 1a, which flange is adapted to be connected to a steering knuckle in a suspension system of a motor vehicle body, the outer ring 1 being constructed as a single piece in its entirety. The flange 1a is provided with a screw hole 14 for fitting the steering knuckle, the hole 14 being defined at a plurality of circumferential locations, and upon engagement of a kingpin (not shown) inserted into a bolt insertion hole in the steering knuckle from the inboard side with the above-described screw hole 14, the vehicle body mounting flange 1a is fitted to the steering knuckle.Also, a side surface of the flange 1a oriented toward the outer side is formed with an arcuate section portion 1aa leading from its base end to the outer periphery of the outer ring 1.

[0041] The inner member 2 serves as a rotating member and is made of a hub axle 9 having a wheel-mounting hub flange 9a, and an inner ring 10 fixed to an outer periphery of an inner end portion of an axle portion 9b of the hub axle 9. The above-mentioned rows of rolling surfaces 4 are formed in the hub axle 9 and the inner ring 10, respectively. A portion of the outer periphery of the inner end portion of the hub axle 9 has a diameter that is reduced radially inward to define an inner ring mounting surface 12, and the above-mentioned inner ring 10 is fixed to this inner ring mounting surface 12. The hub axle 9 has a through hole 11 defined at its center.The hub flange 9a is provided with a plurality of press-fit holes 16 defined at respective circumferential locations, each receiving a corresponding hub bolt 15 that is press-fitted therein. A portion of the hub axle 9 adjacent the root of the hub flange 9a has a cylindrical guide portion 13 defined therein so as to protrude toward the outboard side for guiding the vehicle wheel and a brake component (not shown).

[0042] Fig. Figure 2 illustrates a highlighted front view showing the outer ring 1 of the wheel support bearing assembly as viewed from the outboard side. The body mounting flange 1a has a front highlighted shape having line symmetry with respect to a line segment perpendicular to a bearing axis (for example, an elongated line segment LV or a transverse line segment LH as in Fig. 2) or is of point symmetry about a bearing axis O. More specifically, in the example shown, the front highlighted shape is formed as a round shape having line symmetry with respect to the transverse line segment LH.

[0043] An outer diametrical surface of the outer ring 1, which is the stationary member, is provided with four sensor units 20 (20A, 20B, 20C, and 20D). In the illustrated example, these sensor units 20A to 20D are provided on the respective outer peripheral surface portions of the outer ring in the arcuate portion portion 1aa of the body mounting flange 1a in the outer ring 1 on the outboard side, spaced from each other in an equidistant manner in the circumferential direction thereof.Specifically, two of the sensor units 20A and 20B are provided on upper and lower surface portions of the outer diametrical surface of the outer ring 1, respectively corresponding to upper and lower positions with respect to the tire contact surface, while the remaining two of these sensor units 20C and 20D are provided on left and right surface portions of the outer diametrical surface of the outer ring, respectively corresponding to left and right positions with respect to the tire contact surface. Although not shown, these sensor units 20A and 20B may be provided on the above-mentioned arcuate portion portion 1aa of the flange 1a.

[0044] Also, the sensor units 20A and 20B may be provided at respective positions at which a line segment Lθ containing a center of each of the rolling elements on the outer side and defining a rolling element contact angle passes the outer circumference of the outer member or a position adjacent to these positions as shown in Fig. 1. In the embodiment now being discussed, it is assumed that the respective mounting positions of the sensor units 20A and 20B are located on the respective outer peripheral surface regions of the outer ring adjacent to the outer side of the arcuate portion portion 1aa of the flange 1a and are also located in the above-mentioned line segment Lθ crossing position or the position adjacent to these crossing positions, the above-mentioned crossing positions or the positions adjacent to these crossing positions may be positions separate from the respective outer peripheral surface regions of the outer ring adjacent to the outer side of the arcuate portion portion 1aa.

[0045] Each of these sensor units 20A to 20D is, as best shown in an enlarged plan view in the Fig. 3 and Fig. 4, is made of a strain-generating element 21, and two or more, for example, two in the shown example, strain sensors 22 (22A and 22B) are fitted to the strain-generating element 21 for detecting a strain induced in the strain-generating element 21. The strain-generating element 21 is in the form of a thin plate member made of an elastically deformable metal such as a steel material and has a thickness of not more than 2 mm, and presents a band shape with a uniform width over its entire length when viewed from above, with cutout portions 21b formed in each of the opposite side edge portions of such strain-generating elements 21. Each of the cutout portions 21b has a pair of corner portions presenting an arcuate sectional shape.The strain-generating element 21 also includes two or more, for example, 3 in the example shown, contact fixing segments 21a, which are fixed to the outer diametrical surface of the outer ring 1 in contact therewith by means of respective spacers 23 when they engage between the contact fixing segments 21a and the outer diametrical surface of the outer ring 1. These three contact fixing segments 21a are arranged in a row in a direction along the longitudinal direction of the strain-generating element 21.

[0046] In other words, referring in particular to the Fig. 4, one strain sensor 22a of the strain sensors is arranged between the left contact fixing segment 21a and the intermediate contact fixing segment 21a, and the other strain sensor 22b of the strain sensors is arranged between the intermediate contact fixing segment 21a and the right contact fixing segment 21a. As shown in Fig. 3, the cutout portions 21b are defined at two positions each corresponding to a side on which each of the strain sensors 22 is arranged. Accordingly, the strain sensors 22 detect elongated strains in the vicinity of the cutout portions 21b in the strain-generating member 21. Note that the strain-generating member 21 is preferably of a type that cannot plastically deform even under a condition in which the maximum expected force is applied thereto as an external force acting on the outer ring, the outer ring being the stationary member, or as a working force acting between a wheel tire and a road surface. When the plastic deformation occurs, the deformation of the outer ring 1 is not transmitted to the sensor units 20A to 20D, and therefore, the measurement of the strain is adversely affected.

[0047] Each of the sensor units 20 is arranged such that the three contact fixing elements 21a of the corresponding strain generating element 21 occupy the same position with respect to an axial direction of the outer ring 1 while being held in the respective positions spaced from each other in a circumferential direction of the outer ring 1, wherein these contact fixing segments 21a are secured to the outer circumferential surface of the outer ring by means of associated bolts 24 extending through the associated spacers 23 when engaging between the outer circumferential surface of the outer ring 1 and the contact fixing segments 21a.Each of the above-mentioned bolts 24 extends from a bolt insertion hole 25 defined in the respective contact fixing segments 21a, thereby extending completely in a radial direction of the outer ring 1, and then through a bolt insertion hole 26 defined in the associated spacer 23 into a corresponding screw hole 27 defined in the outer peripheral portion of the outer ring 1. A washer 28 is disposed between a head portion of each of the bolts 24 and the strain-generating member 21.When the contact fixing member 21a is fixed to the outer diametrical surface of the outer ring 1 through the spacer 23 in this manner, portions of the strain-generating member 21 of a thin plate-like configuration in which the cutout portions 21b are formed are in a state separate from the outer diametrical surface of the outer ring 1, and accordingly, strain-induced deformation is enabled in the vicinity of the cutout portions 21b. To enable stable mounting of the sensor units 20A to 20D on the outer diametrical surface of the outer ring 1, a flat portion 1b is formed at a location on the outer diametrical surface of the outer ring 1, to which each of the spacers 23 is fixed on the outer diametrical surface of the outer ring in contact therewith.

[0048] Alternatively, as shown in an enlarged sectional view in Fig. 5, a groove 1c may be provided in the outer diametrical surface of the outer ring 1 at each position between the three sides at which the three contact fixing segments 21a of the strain generating member 21 are fixed to the outer diametrical surface of the outer ring 1, so that the use of the spacers 23 can be eliminated, but that portion of the strain generating member 21 where the cutout portions 21b are positioned may be separated from the outer diametrical surface of the outer ring 1.

[0049] Any of a variety of types can be used for each of the strain sensors 22. For example, the respective strain sensor may be in the form of a metal foil strain gauge. In such a case, its attachment to the strain-generating element 21 is generally achieved by adhesive bonding. Each of the strain sensors 22 may also be in the form of a thick film resistor on the strain-generating element 21.

[0050] The two strain sensors 22a and 22b in each of the sensor units 20A to 20D are provided with a Fig. 1. This evaluation section 45 calculates and evaluates a force F (for example, a vertically acting load Fz) acting on the bearing assembly of a wheel support or acting between the vehicle wheel and the road surface (road surface in wheel contact) from respective sensor output signals of the sensor units 20A to 20D.

[0051] The following describes an example of the load calculation and evaluation performed by the calculation section 45. In general, the relationship between the load vector F acting on the bearing assembly of a wheel support and an output signal vector S of multiple strain sensors can be expressed by the following equation, provided that an offset component within a linear range is accepted: F=M1×S and from the above relationship equation (1), the load F can be determined. It should be noted that the parameter M1 in the above equation (1) represents a predetermined correction coefficient matrix.

[0052] In the calculation section 45 as a calculation process in its initial stage, the sum of and the differences between the respective output signals of the two strain sensors 22a and 22b in each of the sensor units 20A to 20D are calculated, and the sum thereof is taken as an average value A. Also, a variable component is determined from the difference thereof to thereby determine the amplitude value B.

[0053] In the calculation process, in the following stage in the calculation section as a first load evaluation method, using an average vector A corresponding to the average signal of a plurality of sensor units from which the offset component has been removed, the load F is calculated and calculated by the following linear equation in which this variable is multiplied by a predetermined correction coefficient M1: F=M1×A

[0054] Also, in the calculation process in the following stage of the calculation section 45, as a second load-evaluating method, using the previously described mean value vector A and the previously described amplitude value vector B as respective input variables, the load F is calculated and calculated by the following linear equation in which these variables are multiplied by a predetermined correction coefficient M2 and M3: F=M2×A+M3×B The three variables used in this way can further increase the accuracy with which the load is calculated.

[0055] A specific value of each of the above-mentioned correction coefficients applied in the various calculation equations is established through a series of experiments and / or simulations conducted beforehand. The first stress calculation method and the second stress calculation method are carried out indirectly. It should be noted that in the above equation (3), the mean value A, which is variable, can be eliminated. In other words, in the second stress calculation method, the stress F can be calculated and calculated using only the amplitude value B as a variable.

[0056] Respective output signals a and b of the strain sensors 22a and 22b shown in Fig. 6C are affected by an influence of each of the rolling elements 5, which are successively arranged in the vicinity of the installation side on each of the sensor units 20, as shown in Fig. 6B. In other words, the influence of the rolling elements 5 acts on the previously described offset component. Also, when the bearing unit stops, the output signals a and b of these strain sensors 22a and 22b are influenced by the position of each of the rolling elements 5. That is, when each of the rolling elements 5 moves past the position closest to the strain sensors 22a and 22b in the sensor unit 20 (or when each of the rolling elements 5 is held in a position closest to the strain sensors 22a and 22b in the sensor unit 20), the respective output signals a and b of the strain sensors 22a and 22b have the maximum value, and the respective output signals a and b of the strain sensors 22a and 22b decrease when each of the rolling elements 5 moves away from this position (or each of the rolling elements 5 remains in a position away from this position) as shown in the Fig. 6A and Fig. 6B. During the rotation of the bearing unit, each of the rolling elements 5 moves successively over the circumference of the installation side of the sensor unit 20 at intervals of a predetermined arrangement pitch P of the rolling elements 5, and therefore, each of the respective output signals a and b of the strain sensors 22a and 22b represents a waveform similar to a sine waveform in which, as shown by the solid line in Fig. 6C, the amplitude of each of the output signals a and b changes periodically in a cycle equal to the arrangement pitch P of the rolling elements 5.

[0057] In the example now being discussed, the sum of the output signals a and b of the two strain sensors 22a and 22b is taken as the previously described mean value A and the previously described amplitude value B by determining the amplitude from the difference (absolute value) of the amplitudes. Accordingly, the mean value A is a value from which a change component caused by the passage of each of the rolling elements 5 has been subtracted. Also, the amplitude value is less sensitive to the influence of temperature and is therefore stable, and the detection accuracy can be increased by using these two signals.

[0058] In the Fig. 6A to 6C shows an example of the Fig. 5, the sensor unit 20 is comprised of three circumferentially juxtaposed contact mounting segments 21a on the outer diametrical surface of the outer ring 1, which is the stationary member, and two contact mounting segments 21a are positioned at opposite extreme ends of a circumferentially extending row of these contact mounting segments 21a, spaced apart by a distance or interval equal to the pitch P of the rolling elements 5. In such a case, the circumferential distance or interval between the two strain sensors 22a and 22b, which are held in respective positions between the adjacent contact mounting segments 21a, becomes approximately half of the pitch P of the rolling elements 5.As a result, the respective output signals a and b of these two strain sensors 22a and 22b have a phase difference of approximately 180° from each other, and the mean value A, which can be determined from their sum, will be the value from which the component of the change caused by the passage of the rolling elements 5 has been subtracted. The difference is also stable because it is insensitive to the influence of temperature, and since two signals are used, the detected signal can be increased.

[0059] It should be noted that in the Fig. 6A and Fig. 6B, the interval between the contact mounting segments 21a was shown and described as being equal to the arrangement pitch P of the rolling elements 5, and each of the sensors 22a and 22b was shown and described as being in a respective position between the adjacent contact mounting segments 21a, so that the interval between the two strain sensors 22a and 22b in the circumferential direction is approximately equal to half the arrangement pitch P of the rolling elements 5. However, notwithstanding this, the interval between the two strain sensors 22a and 22b in the circumferential direction may be directly selected to be equal to one half of the arrangement pitch P of the rolling elements 5. In such a case, the interval between the two strain sensors 22a and 22b in the circumferential direction may be selected to take a value equal to (1 / 2+n) times the arrangement pitch P of the rolling elements 5, or a value approximately corresponding to such a value.Also in this case, the mean value A, which is determined as the sum of the output signals a and b of the associated strain sensors 22a and 22b, represents a value from which the component of the change caused by the passage of the rolling elements 5 has been subtracted, and the amplitude value B, which can be determined from the difference therefrom, is stable since it is insensitive to the temperature influence and also, since the two signals are used, the detection signal can be increased.

[0060] In the process that takes place in the subsequent stage of the calculation section 45, a selection and output process is performed in which the calculated load value, which can be determined by either the previously described first or second load calculation process, is also selected depending on the rotational speed of a vehicle wheel. More specifically, in the case where the rotational speed of the vehicle wheel is less than a predetermined lower speed limit, the calculated load value resulting from the first load calculation process is selected and output. The above-mentioned predetermined lower speed limit can be selected to have any arbitrarily selected value, and is preferably selected to have a value equal to or less than a person's walking speed (4 km per hour).During low-speed rotation of the vehicle wheel, the processing time required to detect the amplitude of the sensor output signal tends to increase, and during a stop, the detection of the amplitude itself becomes impossible. Accordingly, in the case where the rotation speed of the vehicle wheel is lower than the predetermined lower speed limit, the calculated load value resulting from the first load calculation process, in which only the average value A is used, is selected and output in the manner described above, so that a detected output signal can be output without delay.

[0061] In the now in Fig. 2, the four sensor units 20A to 20D are arranged on the upper surface region, the lower surface region, the left surface region, and the right surface region of the outer diametrical surface of the outer ring 1 serving as a stationary member as already stated, the regions corresponding to the upper and lower and left and right positions with respect to the contact ground surface of the wheel tire, and are spaced at an equal distance at a phase difference of 90° with respect to each other in the circumferential direction, and therefore, the vertically acting load Fz acting on the bearing assembly of a wheel support, a load Fx corresponding to a driving force or a braking force, and an axially acting force Fy can be determined.

[0062] When the load acts between the vehicle wheel tire and the road surface, this load is also applied to the outer ring 1, which is the stationary member of the bearing assembly of a wheel support, accompanied by deformation. In the example shown, since the two or more contact attachment segments 21a of the strain-generating element 21 in each of the sensor units 20A to 20D are attached to the outer ring 1 in contact therewith, the strain induced in the outer ring 1 is easily transmitted to the strain-generating element 21 after reinforcement, and such strain can therefore be detected by the strain sensors 22a and 22b with high sensitivity.

[0063] In particular, since the body mounting flange 1a has its front prominent shape, which exhibits line symmetry with respect to the line segment perpendicular to the bearing axis or point symmetry around the bearing axis, the shape of the outer ring is simplified, and the temperature distribution resulting from a complication of the outer ring shape and the variation in the expansion-contraction amount can be reduced. This allows the sensor units 20A to 20B to detect the strain amount resulting from the load while significantly reducing the influence caused by the temperature distribution in the outer ring 1 and the variation in the expansion-contraction amount.Also, in addition to the above-described simplification of the outer ring shape, since the sensor units 20A to 20D are provided in the arcuate portion 1aa of the flange 1a formed in the outer periphery of the outer ring 1 so as to extend from a base end of a side of the flange 1a oriented toward the outer side to the outer periphery of the outer ring 1 or an outer peripheral surface portion of the outer ring adjacent to the arcuate portion 1aa on the outer side, the strain induced at the installation sides of the sensor units 20A to 20D becomes large, and even if a variation in the temperature distribution of the outer ring 1 and the expansion-contraction amount occurs, their influence can be minimized to enable the sensor units 20a to 20d to detect the strain amount caused by the load.Accordingly, the load acting on the vehicle wheel can be accurately determined while eliminating the detection errors resulting from the shape of the outer ring.

[0064] In the case where the outer peripheral surface area of ​​the outer ring is adjacent to the arcuate portion area 1aa on the outside side, the area 1aa on the outer periphery of the outer ring 1 being formed so as to extend from a base end of a side of the flange 1a oriented toward the outside side to the outer periphery of the outer ring 1, the sensor units 20A to 20D may be provided on the outer peripheral surface area of ​​the outer ring in a region axially spaced within 5 mm from a terminating end of the arcuate portion area 1aa, as in the embodiment of a Fig. 7 is applied. If the installation sides of the sensor units 20A to 20D are selected within a range spaced within 5 mm in the axial direction from the terminating end of the arcuate portion 1aa in the manner described above, even if variations occur in the temperature distribution of the outer ring 1 and the expansion-contraction amount, their influence can be minimized to enable the sensor units 20A to 20D to detect the strain amount caused by the load.

[0065] Also, in addition to the above-described simplification of the shape of the outer ring, since the sensor units 20A to 20D are provided at respective positions crossing the line segment Lθ extending through the center of each of the rolling elements on the outside side in the direction required to form the contact angle of the rolling elements, or at respective positions adjacent to these crossing positions, the strain induced on the installation side of the sensor units 20A to 20D becomes large, and even if variations in the temperature distribution of the outer ring 1 and the expansion-contraction amount occur, their influence can be minimized to enable the sensor units 20A to 20D to detect the strain amount caused by the load.Accordingly, the load acting on the vehicle wheel can be accurately calculated by canceling the detection errors caused by the shape of the outer ring.

[0066] Also, since the sensor units 20A to 20D are used in plural numbers (four in the example shown), and these sensor units 20A to 20D are provided at equal intervals in the circumferential direction of the outer periphery of the outer ring 1, the sensor units 20A to 20D can be arranged at respective positions similar to each other in temperature distribution and expansion-contraction amount, and the sensor units 20A to 20D can be enabled to detect the strain amount caused by the load while minimizing the influence of the temperature distribution and the variation in the expansion-contraction amount. Accordingly, by canceling the detection error caused by the shape of the outer ring, the load acting on the vehicle wheel can be accurately calculated.

[0067] It should be noted that, in the description of the above-mentioned embodiment, a plurality of conditions must be met at the installation sides of the sensor units 20A to 20D, which have been shown and specified. However, in addition to simplifying the shape of the outer ring, the installation side of each of the sensor units 20A to 20D can satisfy at least one of the conditions for installing the sensor units, and thereby the load acting on the vehicle wheel can be accurately calculated by canceling the detection error caused by the shape of the outer ring. Also, in this embodiment, the use of four sensor units 20A to 20D was shown and described, but the number of sensor units 20 that can be used may be only one.

[0068] Fig. Figure 8 is a longitudinal sectional view of a third embodiment of the sensor-equipped wheel support bearing assembly constructed in accordance with the present invention, and Fig. 9 is a front elevational view showing the outer ring as viewed from the outboard side. In this third embodiment, the body mounting flange 1a of the outer ring 1, which is employed in the embodiment of each of the previously described embodiments, is omitted, and instead, the inner end portion of the outer ring 1 is provided with a radially inwardly depressed portion 1d having an outer periphery formed with an externally threaded portion 1da for attachment to the steering knuckle. With the externally threaded portion 1da in the radially inwardly depressed portion 1d threadably engaged with an internally threaded portion 17a in an inner periphery of the steering knuckle 17, the outer ring 1 can be attached to the steering knuckle 17. Structural features other than those described above are similar to those employed in each of the previously described embodiments of the present invention.

[0069] That is, with respect to the conditions that the installation side of each of the sensor units 20A to 20D should satisfy, and since no body mounting flange exists in the outer ring 1, the condition that each sensor unit 20A to 20D should be installed on the arcuate portion 1aa or on the outer peripheral surface portion of the outer ring adjacent to the arcuate portion 1aa on the outside side no longer exists, but the other conditions for installation remain the same as in each of the previously described embodiments.

[0070] As described above, in this embodiment, since the use of the body mounting flange on the outer ring 1 is omitted, and instead the inner end portion of the outer ring 1 is formed with a radially inwardly pushed portion 1d having the male thread portion 1da on the outer periphery thereof for attachment to the steering knuckle 16, whereby the outer ring 1 is fixed to the steering knuckle 16 with the male thread portion 1da threadedly engaged in the female thread portion 16a defined on the inner periphery of the steering knuckle 16, the shape of the outer ring can be simplified, and the temperature distribution and the variation in the expansion-contraction amount caused by the complication of the shape of the outer ring can be reduced.Accordingly, the sensor units 20A to 20D can be enabled to detect the amount of strain caused by the load, while the temperature distribution in the outer ring and the influence caused by the variation of the expansion-contraction are significantly reduced.Also, in addition to simplifying the shape of the outer ring, since the sensor units 20A to 20D are provided at the respective positions crossing the line segment Lθ, the line segment extending through the center of each of the rolling elements on the outer side in the direction required to form the contact angle of the rolling elements, or through respective positions adjacent to these crossing positions, the strain induced at the installation sides of the sensor units 20A to 20D becomes large, and even if variations in the temperature distribution of the outer ring 1 and the expansion-contraction amount occur, their influence can be minimized to enable the sensor units 20A to 20D to detect the strain amount caused by the load.Accordingly, the load acting on the vehicle wheel can be accurately determined by eliminating the detection error resulting from the shape of the outer ring.

[0071] Also, since the sensor units 20A to 20D are used in a plurality (four in the example shown) and these sensor units 20A to 20D are provided at equal intervals in the circumferential direction of the outer periphery of the outer ring 1, the sensor units 20A to 20D can be arranged at respective positions similar to each other in terms of temperature distribution and expansion-contraction amount, and the sensor units 20A to 20D can be enabled to detect the amount of strain caused by the load while minimizing the influence of the temperature distribution and the variation in the expansion-contraction amount. Accordingly, the load acting on the vehicle wheel can be accurately calculated, with the detection error caused by the shape of the outer ring being canceled.

[0072] A fourth embodiment of the present invention will now be described with reference to the Fig. 10 to Fig. 20A to 20C. It should be noted that in these figures, the component parts similar to those described with reference to Fig. 1 to Fig. 6A to 6C are in connection with the previously described first embodiment of the present invention, are designated by like reference numerals, and therefore, their details are not repeated for the sake of brevity. In this fourth embodiment, the plurality of sensor units 20A to 20D are surrounded by a protective sheet 29 for enclosing the outer periphery of the outer ring 1, and this feature distinguishes the fourth embodiment from the previously described first embodiment.

[0073] Fig. 11 corresponds to Fig. 2 includes the above-described first embodiment and is a highlighted front view showing the outer ring 1 of the bearing assembly of a wheel support according to the fourth embodiment, viewed from the outside. Component parts similar to those in Fig. 2 are marked with the same reference numerals and therefore their details are not repeated for the sake of brevity. In comparison to Fig. 2 differs Fig. 11 of the Fig. 2 with respect to the use of a signal deriving region 32b, as will be described later.

[0074] Fig. 14 and Fig. 15 correspond to the Fig. 3 and Fig. 4 containing the previously described first embodiment and component parts which are similar to those in Fig. 3 and Fig. 4 are identified by the same reference numerals and therefore their details are not repeated for the sake of brevity. However, each of the Fig. 14 and Fig. 15 shown sensor units 20A to 20D from those in Fig. 3 and Fig. 4 with respect to the use of a flexible substrate 30 on the back of the strain-generating element 21, as will be explained in detail later.

[0075] Each of the sensor units 20A to 20D is arranged such that the three contact fixing segments 21a of the corresponding strain generating element 21 occupy the same position with respect to the axial direction of the outer ring 1, which is an outer member, while these three contact fixing segments 21a are held in respective positions spaced from each other in a circumferential direction of the outer ring 1. These contact fixing segments 21a are fixed to the outer surface of the outer ring 1 through the flexible substrate 30 and spacers 23 by means of associated bolts 24. The flexible substrate 30 is a single plate-like substrate to be arranged in a ring shape along the outer circumferential surface of the outer member 1.In other words, the four sensor units 20A to 20D are mounted on the single flexible substrate 30 and are in turn fixed to the outer peripheral surface of the outer ring 1 together with the flexible substrate 30. Each of the bolts 20 is inserted into the corresponding bolt insertion hole 25 defined in each of the contact fixing segments 21a so that the bolts extend in the radial direction and then through a corresponding bolt insertion hole 30a defined in the flexible substrate 30 and a corresponding bolt insertion hole 126 similarly defined in the respective spacer 23, and is in turn firmly screwed into the screw hole 27 defined in the outer peripheral portion of the outer ring 1. With the sensor units 20A to 20D fitted to the flexible substrate 30 in the manner described above, customization of the sensor units 20A to 20D can be enabled.

[0076] The above-mentioned four sensor units 20A to 20D are in a ring shape with electronic component parts including, among others, a signal processing IC 31 and a signal cable 32 (best in the Fig. 16A, Fig. 16B) for conducting the processed output signal to the outside of the bearing unit to form a sensor array 33, and the sensor array 33 in the ring shape is in turn fitted to the outer peripheral surface of the outer ring 1 in a coaxial relationship therewith. Since this time the flexible substrate 30 is arranged in a ring shape so as to extend along the outer peripheral surface of the outer ring 1, polyimide is a preferred base material therefor. When polyimide is selected as the base material for the flexible substrate 30, the flexible substrate 30 can have sufficient flexibility and heat resistance, and the flexible substrate 30 can be easily processed to extend in the circumferential direction of the outer ring 1.

[0077] Fig. 16A and Fig. 16B illustrates an example of an arrangement of the electronic component parts in the sensor assembly 33 in a developed plan view and a side view, respectively. In this arrangement example, the signal processing IC 31 and a lead portion 32a of the signal cable 32 are directly mounted on the flexible substrate 30 together with the four sensor units 20A to 20D. The sensor units 20A to 20D are mounted on a back surface (a surface opposite to the outer peripheral surface of the outer ring 1) of the flexible substrate 30, and the signal processing IC 31 is mounted on a front surface of the flexible substrate 30.By fitting the sensor units 20A to 20D, the signal processing IC 31, and the signal cable 32 onto the flexible substrate 30 in the manner described above while forming a pattern of a circuit on the flexible substrate 30, connection between the sensor units 20A to 20D, the signal processing IC 31, and the signal cable 32 can be enabled.

[0078] Also, a circuit 34 connecting each of the sensor units 20A to 20D, the signal processing IC 31, and the signal cable interconnection portion 32a is printed on the flexible substrate 30 as a circuit pattern. The sensor units 20A to 20D and the signal processing IC 31 are connected to the circuit 34, for example, by soldering, and the signal extraction portion 32b for extracting the signal cable 32 to the body side is connected to the signal cable interconnection portion 32a, for example, by soldering.The sensor units 20A to 20D are configured such that the respective surfaces of the strain-generating elements 21 are opposite to the surfaces in contact with the outer ring 1, and are formed as circuit-printed surfaces. These circuit-printed surfaces are fitted to the flexible substrate 30 so as to face a printed surface of the circuit 34 of the flexible substrate 30. In the example shown, portions of the flexible substrate 30 corresponding to opposite side portions of the sensor units 20A to 20D in an installation side of the sensor units 20 are formed with band-shaped openings 30b extending in a longitudinal direction of the flexible substrate 30.Accordingly, corrosive surfaces of the sensor units 20A to 20D become flat surfaces with the outer ring 1, with neither a circuit printed surface nor solder metal present, and the sensor units 20A to 20D can be cohesively fitted to the outer ring 1.

[0079] The signal processing IC 31 may serve as a calculation section for calculating a force (a vertically acting load Fz, a load Fx becoming a driving force or a braking force, an axially acting load Fy) acting on the bearing assembly of a wheel support or between the vehicle wheel and the road surface (tire contact base area) with respect to the respective output signals of the strain sensors 21a and 22b, and may include a signal processing circuit for performing processing of the strain signal and a correction circuit.The signal processing IC 31 includes a ratio setting segment (not shown) in which the ratios between the above-described force and the respective output signals of the strain sensors 22a and 22b are set, for example, using calculation equations or tables, and which outputs a working force from the output signals of the sensor units 20A to 20D using the ratio setting segment. The content of the ratio setting segment is determined and set in advance through a series of experiments and / or simulations.

[0080] An example of strain calculation in the signal processing IC 31 will now be described in detail. In the signal processing IC 31, as a first-stage process, the sum of the output signals of the two strain sensors 22a and 22b of the sensor units 20A to 20D is calculated and then derived as an average value A. Also, by calculating the difference between the respective output signals of the two strain sensors 22a and 22b and deriving a change component therefrom, the amplitude value B is determined.

[0081] In the process at the next stage, the signal processing IC 31 uses the above-mentioned mean value A and the amplitude value B to calculate and compute the load F acting on the bearing assembly of a wheel support in the following manner. In the following description, the details are not repeated for the sake of brevity, since the load calculation in the signal processing IC 31 is substantially similar to that in the calculation section 45 described above.

[0082] To describe the influence caused by the rolling elements 5 on the output signals of the sensor units 20A to 20D in the Fig. 20A to 20C, the description relating to the Fig. 6A to 6C were applied in conjunction with the first embodiment of the present invention described above, and therefore these details are not repeated for the sake of brevity. However, it should be noted that the difference between the Fig. 20A to 20C and Fig. 6A to 6C only consists in the use of the flexible substrate 30, which, as shown in the Fig. 20A in contrast to Fig. 6A is used. The sensor units are fitted to the flexible substrate, and the sensor assembly formed by connecting the electronic component parts in a ring shape, which includes the sensor units 20A to 20D, the signal processing IC for processing the respective output signals of the sensor units 20A to 20D, and the signal cable for leading the processed output signals to the outside of the bearing unit, is fitted to the outer peripheral surface of the outer ring in a coaxial manner with the outer ring and the electronic component parts including the sensor units 20A to 20D, and this sensor assembly may be surrounded by a protective sheet. In the case of this construction, the sensor assembly in which the electronic component parts including the sensor units 20A to 20D are connected in the ring shape may be covered with the protective sheet 29.

[0083] The calculated load value determined by the signal processing IC 31 in accordance with the first and second load calculation processes is output by switching and selecting depending on the rotation speed of the vehicle wheel. Specifically, in the case where the rotation speed of the vehicle wheel is less than a predetermined lower speed limit, the calculated load value resulting from the first load calculation process can be selected and output. The above-mentioned predetermined lower speed limit can be selected from an arbitrarily selected value, but is preferably selected from a value equal to or lower than a person's walking speed (4 km per hour).During low-speed rotation of the vehicle wheel, the processing time required to detect the amplitude of the sensor output signal tends to increase, and during a stop, the detection of the amplitude itself becomes impossible. Accordingly, in the case where the rotation speed of the vehicle wheel is lower than the predetermined lower speed limit, the calculated load value resulting from the first calculation load process, in which only the average value A is used, is selected and output in the manner described above, so that a detected load signal can be output without delay.

[0084] In the embodiment now being discussed, as in Fig. As shown in Figure 11, the four sensor units 20A to 20D are arranged on the upper surface region, the lower surface region, the left surface region, and the right surface region of the outer diametrical surface of the outer ring 1, which regions correspond to the upper, lower, and left and right positions with respect to the contact surface of the wheel tire, and which are equally spaced with a phase difference of 90° with respect to each other in the circumferential direction. Therefore, the vertically acting load Fz acting on the bearing assembly of a wheel support, the load Fx that becomes a driving force or a braking force, and the axially acting load Fy can be determined.

[0085] The sensor assembly 33, which is adapted to the outer circumferential surface of the outer ring 1, is connected to the protective plate 29 in a manner as best shown in Fig. 10. The fender 29 is a tubular member surrounding the outer periphery of the outer member 1 and having an outer end portion fixed or fitted to the outer peripheral surface of the outer ring 1. An inner end portion of the fender 29 opposite to the outer end portion thereof is provided with a rim member 35 made of an annular elastic member and extending along its open edge, the rim member 35 being held in contact with an outwardly facing side surface of the vehicle mounting flange 1a of the outer ring 1. Accordingly, a tight seal is established between the outer and inner end portions of the fender and the outer peripheral surface. The rim member 35 can be held in contact with the above-mentioned outer peripheral surface of the flange 1a.

[0086] The material forming the edge element 35 is preferably used in the form of a rubber material. With this choice, the sealability between the edge element 35 and the inner end region of the protective plate 29 can be ensured. In addition to the above, the edge element 35 can be formed integrally with the protective plate 29. However, in the example shown, as best shown in Fig. 12 in an enlarged detail, the edge element 35 has a shape that widens outward toward the inner end region. Accordingly, unwanted penetration of, for example, muddy water or salt water through the inner end region of the fender 29 into the inside of the fender 29 can be reliably prevented.

[0087] The fender 29 is formed, for example, from a corrosion-resistant steel plate using a press. Accordingly, corrosion of the fender 29 due to external environmental influences can be prevented. In addition to the above, the fender 29 can be formed from a steel plate using a press with a metal plate, or by applying a coating process to its surface. Even in this case, undesirable corrosion of the fender 29 due to external environmental influences can be prevented. The material for the fender 29 can be plastic, rubber, or steel.

[0088] As in Fig. 13, which is a cross-sectional view along the line XIII-XIII in Fig. As shown in Fig. 11, the inner end portion of the protective plate 29 is provided with a vent hole 36 through which the signal cable vent portion 32b of the signal cable 32 in the sensor assembly 33 is drawn outward, and a sealing material 37 is applied around the portion of the signal cable vent portion 32b extending through the vent hole 36. Accordingly, it is possible to ensure the sealability of this portion of the signal cable vent portion 32b drawn outward from the protective plate 29.

[0089] Fig. 17A and Fig. 17B illustrates another example of the arrangement of the electronic component parts in the sensor assembly 33 surrounded by the protective sheet 29, in a plan view and a cross-sectional view, respectively. Even in this example of the arrangement of the electronic component parts, all of the sensor units 20A to 20D, the signal processing IC 31, and the circuit portion 32a of the signal cable are mounted on the flexible substrate 30. In this example of the arrangement, a rectangular opening 30c is formed on the flexible substrate 30 on the side of the assembly of the sensor unit 20, through which substantially the entire body of the sensor unit 20 is exposed.By forming the rectangular openings 30c, through which substantially the entire body of the sensor units 20A to 20D is exposed, on the installation sides of the sensor units 20A to 20B on the flexible substrate 30, it is possible to avoid the possibility that the deformation of the strain-generating elements 21 in the sensor units 20A to 20D can be regulated by the flexible substrate 30, and therefore, the stress detection accuracy can be increased accordingly. Structural features other than those described above are similar to those in the example of the sensor units shown in FIGS. Fig. 16A and Fig. 16B shown arrangement.

[0090] Fig. 18A and Fig. 18B illustrate another example of an arrangement of the electronic component parts in the sensor assembly 33 surrounded by the protective sheet 29, in a plan view and a cross-sectional view, respectively. In this example of the arrangement of the electronic component parts, the sensor units 20A to 20D are separated from the flexible substrate 30 except for the respective portions connected to the circuit 34 on the flexible substrate 30. Also, a portion of the flexible substrate 30 to which the signal processing IC 31 is fitted is formed with a large cross-sectional area, so that the remaining portion of the flexible substrate 30 has a smaller cross-sectional area on which the sensor units 20A to 20D are arranged, thereby avoiding an increase in the width of the entire structure in this arrangement. Accordingly, the sensor assembly 33 can be constructed compactly.Other structural features than those described above are similar to those in the example of the one shown in the . Fig. 16A and Fig. 16B shown arrangement.

[0091] Fig. 19A and Fig. 19B illustrate yet another example of an arrangement of the electronic component parts in the sensor assembly 33 surrounded by the protective sheet 29, in a plan view and a sectional view, respectively. Even in this example of the arrangement of the electronic components, as is the case with the example of the arrangement of the sensor assembly 33 with respect to the Fig. 18A and Fig. 18B, the sensor units 20A to 20D are separated from the flexible substrate 30 except for the respective regions connected to the circuit 34 on the flexible substrate. However, in this example of the arrangement, the flexible substrate 30 is formed in the shape of a tape with a uniform width over its entire length, and the sensor units 20A and 20D are arranged at a side region of the thus flexible substrate 30 along the flexible substrate 30. Other structural features than those described above are similar to those in the example of the arrangement shown in the Fig. 16A and Fig. 16B shown arrangement.

[0092] The assembly of the sensor-equipped wheel support bearing assembly is carried out in the following sequence. Initially, when the outer ring 1 is in the simple body condition, or the rolling elements 5 have been mounted on the outer ring 1, the sensor assembly 33 comprising the electronic component parts including the sensor units 20A to 20D is fitted to the outer peripheral surface of the outer ring 1.Then, the tubular fender 29 is press-fitted from the outer side of the outer ring 1 to the outer peripheral surface of the outer ring 1 with its outer end fixed to the outer peripheral surface of the outer ring 1, and the edge member 35 at the inner end of the fender 29 is brought into contact with the outer side surface of the vehicle mounting flange 1a of the outer ring 1 or its outer peripheral surface, thereby allowing the sensor assembly 33, which is made of the electronic component parts including the sensor units 20A to 20D, to be enclosed by the fender 29. Subsequently, the entire bearing unit is assembled.When assembled in the manner described above, the sensor-equipped bearing assembly of a wheel support comprising the sensor units 20A to 20D adapted to the outer ring 1 or the sensor assembly 33 comprising the sensor units 20A to 20D enclosed by the fender 29 can be easily assembled.

[0093] The load-detecting operation performed by the sensor-equipped wheel support bearing assembly according to the above construction is substantially similar to the operation performed by the sensor-equipped wheel support bearing assembly designed according to the first embodiment described above, and therefore, its details will not be repeated for the sake of brevity. However, in the embodiment now being discussed, since the plurality of sensor units 20A to 20D are surrounded by the tubular shroud 29 for enclosing the outer periphery of the outer member 1, which is a stationary member, and since the outer end of this shroud 29 is fixed to the outer peripheral surface of the outer ring 1, and since the rim member 35 made of the annular elastic member is provided along the open edge of the inner end portion of the shroud 29,By maintaining the outer side surface of the body mounting flange 1a of the outer ring 1 or its outer peripheral surface, not only can unwanted troubles (damage caused by impacting pebbles and / or corrosion caused by muddy water or salt water) be prevented from occurring in some or all of the sensor units 20A to 20D under the influence of the external environment, but also the stress can be accurately detected over a longer period of time, and therefore, the assembly of the sensor units 20A to 20D and the wiring of the signal cable 32 can be achieved easily and at a reduced cost.

[0094] In the above description, reference was made to the detection of the working force developed between the vehicle wheel tire and the vehicle surface. However, not only the working force developed between the vehicle wheel tire and the road surface can be detected, but also the force acting on the wheel support bearing assembly (for example, a preload amount). When the detected load obtained from this sensor-equipped wheel support bearing assembly is used in a vehicle control system, it can contribute to the stable driving of the vehicle. Also, when this sensor-equipped wheel support bearing assembly is used, the load sensor can be compactly installed in the vehicle, thereby achieving excellent mass productivity and cost reduction.

[0095] Also, in this embodiment, since the electronic component parts including the sensor units 20A to 20D, the signal processing IC 31 for processing the respective output signals of the sensor units 20A to 20D, and the signal cable 32 for outputting the processed output signals to the outside of the bearing assembly of a wheel support in the ring shape are connected to complete the sensor assembly 33, and since this sensor assembly 33 is fitted to the outer peripheral surface of the outer member 1, which is the stationary member, in a coaxial manner with the outer ring 1 and is covered by the fender 29, not only the sensor units 20A to 20D but also the remaining electronic component parts such as the signal processing IC 31 constituting the sensor assembly 33 and the signal cable 32 can be protected from any problem caused by the influence of the external environment.

[0096] Fig. 21 illustrates a fifth embodiment of the present invention. The sensor-equipped bearing assembly of a wheel support designed according to this fifth embodiment is similar to that designed according to the fourth embodiment and with respect to the Fig. 10 to Fig. 20A to 20C, but differs from this in that at least a portion of the outer peripheral surface of the outer ring 1, to which the sensor units 20A to 20D are fitted, the portion being in contact with at least the sensor units 20A to 20D, is formed with a surface-treated layer 38 having a corrosion resistance or anti-corrosive property. However, in the example shown, the surface-treated layer 38 is formed over the entire area of ​​the outer peripheral surface of the outer ring 1, but the surface-treated layer 38 may also be formed in only a portion of the outer peripheral surface on the outboard side of the vehicle mounting flange 1a.

[0097] Examples of the surface-treated layer 38 having corrosion resistance or anti-corrosive properties include, for example, a metal-plated layer formed by a metal plating method, a paint film formed by a painting technique, or a coated layer formed by a coating technique. In the metal plating technique, any coating method such as zinc plating, unichrome plating, chromate plating, nickel plating, chromium plating, nickel electroplating, Kanigen plating (electroplating), and iron tetraoxide film (black oxide finish) can be used. In the painting technique, any electrodeposition coating such as cation electrodeposition coating, anion electrodeposition coating, or fluorine-based electrodeposition coating can be used.In the implementation of the coating technology, any coating process can be used, such as ceramic coating of, for example, silicon nitride.

[0098] As described above, by forming the surface-treated layer 38 of the type having corrosion resistance or anti-corrosive property at least on the contact portions of the sensor units 20A to 20D on the outer peripheral surface of the outer ring 1, which is the stationary member, buildup on the installation side of the sensor units 20A to 20D, which may be caused by rusting occurring in the outer peripheral surface of the outer ring 1, and undesirable development of inherited rust in some or all of the sensor units 20A to 20D can be avoided, erroneous operation of some or all of the strain sensors 22a and 22b, which may result from the rusting, can be eliminated, and strain detection can be performed accurately for a longer period of time.Also, where the outer peripheral surface of the outer member 1, to which the sensor assembly 33 including the sensor units 20A to 20D is fitted, is formed with the above-described surface-treated layer, undesirable buildup of the installation sides of the sensor assembly 33 caused by rusting can be avoided, and faulty operation of the strain sensors 22a and 22b caused by the rusting can be further eliminated.

[0099] Even if the formation of the surface-treated layer 38 is limited only to the portion of the outer peripheral surface of the outer ring 1 on the outer side of the vehicle mounting flange 1a, a surface-untreated portion can be maintained at a portion of the outer peripheral surface of the outer ring at the inner end portion during grinding of the rolling surfaces of the outer ring 1, and therefore, the rolling surfaces 3 can be accurately ground.

[0100] Fig. 22 and Fig. 23 illustrate a sixth embodiment of the present invention. The sensor-equipped bearing assembly of a wheel support designed according to the sixth embodiment is similar to that according to the fourth embodiment, which is Fig. 10 to Fig. 20A to 20C, differs therefrom, however, in that the outer end of the protective plate 29 is exposed to the outer side of the outer ring 1, and a non-contact gap 39 forming a labyrinth seal is formed between such outer end and the inner element 2, which is the rotating element. In particular, in the example shown, as best shown in the Fig. 23 in an enlarged fragmentary view, the outer end of the fender 29 is formed with an inwardly bent portion 29a which is bent radially inward so as to extend along the outer end of the outer ring, is then bent radially upward from a tip of the inwardly bent portion 29a to form an outwardly bent portion 29b which overlaps the inwardly bent portion 29a, and is then formed with a tubular portion 29c which extends from a tip of the outwardly bent portion 29b toward a bent portion 9aa at a base portion of the hub flange 9a of the inner member 2. Accordingly, a non-contact sealing gap 39 having a narrow width is formed between a portion ranging from the outwardly bent portion 29b to the tubular portion 29c and the bent portion 9aa at the base portion of the hub flange 9a.Other structural features than those described above are similar to those employed in the embodiment of the fourth embodiment described with reference to FIG. Fig. 10 to Fig. 20A to 20C are shown and described.

[0101] When the non-contact sealing gap 39 is formed between the outer end of the shroud 29 and the inner member 2 as described above, the sealability of the shroud 29 at the outer end is increased to surely prevent the occurrence of any problems in the sensor caused by the influence of the external environment, and therefore the stress detection can be accurately performed.

[0102] Fig. 24 and Fig. 25 illustrate a seventh embodiment of the invention. The sensor-equipped bearing assembly of a wheel support designed according to the seventh embodiment is similar to the sensor-equipped bearing assembly of a wheel support according to the sixth embodiment described with reference to Fig. 22 and Fig. 23, however, differs therefrom in that a tubular portion 29c at the tip of the outwardly bent portion 29b at the outer end of the fender 29 is formed to constitute an L-shaped portion extending along a side surface of the hub flange 9a, as best seen in Fig. 25 in an enlarged sectional view. Other structural features than those described above are similar to those used in the sixth embodiment described with reference to Fig. 22 and Fig. 23 shown and described.

[0103] As described above, when the tubular portion 29c at the tip of the outwardly bent portion 29b at the outer end of the fender 29 is formed as an L-shaped portion so as to extend along the side surface of the hub flange 9a, a non-contact sealing gap 39 is formed between a portion extending from the outwardly bent portion 29b to the tubular portion 29c and the base portion of the bent portion 9aa of the hub flange 9a, which represents such a shape as to extend along the side surface of the hub flange 9a. Accordingly, at the outer side of the fender 29, a flow of intruding muddy water or the like is allowed to the outside through the non-contact sealing gap 39 extending along the side surface of the hub flange 9a, and therefore the sealability of the fender 29 at the outer end is further increased.

[0104] Fig. 26 and Fig. 27 illustrate an eighth embodiment of the present invention. The sensor-equipped bearing assembly of a wheel support constructed according to this eighth embodiment is similar to the sensor-equipped bearing assembly of a wheel support constructed according to the sixth embodiment, which is Fig. 22 and Fig. 23, however, differs in that the outwardly bent portion 29b at the outboard end of the fender 29 further extends to an outer diametrical side beyond an outer diametrical side base end of the inwardly bent portion 29a, as best seen in Fig. 27 in an enlarged detail view. Other structural features than those described above are similar to those shown in the sixth embodiment, which is shown in relation to the Fig. 22 and Fig. 23 shown and described.

[0105] As described hereinabove, when the outwardly bent portion 29b at the outer end of the shield 29 extends further toward the outer diametrical side beyond the outer diametrical side base end of the inwardly bent portion 29a, the radial distance of the non-contact seal gap 39 formed between this portion extending from the outwardly bent portion 29b to the tubular portion 29c and the hub flange 29a is increased. Accordingly, the sealability of the shield 29 at the outer end is further enhanced.

[0106] Fig. 28 and Fig. 29 illustrate a ninth embodiment of the present invention. In the sensor-equipped wheel support bearing assembly designed according to this embodiment, as best shown in Fig. 29 in an enlarged fragmentary view, the outer end of the fender 29 is made to extend outward toward the outer side beyond the outer end of the fender 29, an outwardly bent portion 29d bent from such outer end toward the outer diametrical side is formed, an inwardly bent portion 29e is formed by bending a tip of the outwardly bent portion 29d in an inner diametrical side so as to overlap with the outwardly bent portion 29d, and a tubular portion 29f extending from a tip of the inwardly bent portion 29e toward a bent portion 9aa at a base portion of the hub flange 9a of the inner member 2 is finally formed.Accordingly, a non-contact seal gap 39 having a narrow width configuration is formed elongated in a radial direction between a portion extending from the inwardly bent portion 29e to the tubular portion 29f. Structural features other than those described above are similar to those described in the fourth embodiment described with reference to FIG. Fig. 10 to Fig. 20A to 20C are shown and described.

[0107] Even in this case, in which the non-contact sealing gap 39 having the narrow width and extending in the radial direction is formed at the outer end of the shroud 29 between the portion ranging from the inwardly bent portion 29e to the tubular portion 29f and the base portion of the bent portion 9aa of the hub flange 9aa, the sealability at the outer end of the shroud 29 is increased to surely avoid any problems in the sensor caused by the influence of the external environment, and therefore the load detection can be accurately performed.

[0108] A tenth embodiment of the invention will now be described with particular reference to the Fig. 30 to 33. It should be noted that in these figures relating to the tenth embodiment, the component parts are similar to those described with respect to the Fig. 10 to Fig. 20A to 20C in connection with the fourth embodiment described above are designated by like reference numerals and therefore their details will not be repeated for the sake of brevity.

[0109] Fig. 31 is one of the Fig. 11 corresponding figure, which is directed to the fourth embodiment, and with the exception that this differs from Fig. 11 in terms of the position at which the sealing material 37 is applied in the area where the lead-out portion 32b of the signal cable is drawn, other structural features thereof are similar to those in Fig. 11 shown.

[0110] In the case of this tenth embodiment, in contrast to the fourth embodiment described above, best in Fig. 10, the protective sheet 29 used to enclose the outer periphery of the outer ring 1 is shaped to gradually widen outward, with its outer diameter increasing from the outer side toward the inner side.Moreover, while in the fourth embodiment described above, the inboard end of the fender 29 is provided with the rim member 35 made of an annular elastic member so as to extend along its open edge, and this rim member 35 is held in contact with the outwardly facing side surface of the vehicle mounting flange 1a of the outer ring 1, the tenth embodiment is such that the outboard end of the fender 29 is provided with the rim member 35 made of the annular elastic member so as to extend along its open edge, and this rim member 35 is held in contact with the outer peripheral surface of the outer ring 1.Accordingly, a seal is established between the outer end of the guard plate 29 and the outer peripheral surface of the outer ring 1, and also between the inner end of the guard plate 29 and the outer diametrical surface of the flange 1a of the outer ring 1. Therefore, unwanted intrusion of, for example, muddy water and / or salt water from the outer end in an inward direction of the guard plate 29 can be reliably prevented, allowing load detection to be performed accurately. Structural features other than those described above are similar to those used in the fourth embodiment.

[0111] The rim member 35 also has a portion extending toward a portion of an outer peripheral surface of the fender 29 to define a fender outer peripheral surface covering portion 35a. Accordingly, at the outer end of the outer peripheral surface of the fender 29, a wall formed by the fender outer peripheral surface covering portion 35a protrudes radially outward. In the presence of this wall, unwanted inflow of muddy water and / or salt water into a portion where the rim member 35 is held in contact with the outer peripheral surface of the outer ring 1 can be prevented, thereby securely preventing unwanted intrusion of muddy water and / or salt water into the fender 29.The fender outer peripheral surface covering portion 35a, when fitted to the outer peripheral surface of the fender 29, is provided to extend toward the inner side beyond a region in which it is positioned in the outer peripheral surface of the fender 29 to ensure a required strength of fitting.

[0112] The assembly of this sensor-equipped wheel support bearing assembly is similar to that of the sensor-equipped wheel support bearing assembly configured according to the fourth embodiment described above, but differs therefrom in the feature that the rim member 35 at the outer end of the fender 29 is held in contact with the outer peripheral surface of the outer ring 1, and the sensor assembly 33 composed of the electronic component parts including the sensor units 20a and 20d is surrounded by the fender 29, and therefore, the details of other assembly methods described in connection with the fourth embodiment will not be repeated for the sake of brevity.

[0113] Since the load detection operation performed in the sensor-equipped wheel support bearing assembly according to the tenth embodiment of the present invention is substantially the same as that in the sensor-equipped wheel support bearing assembly according to the fourth embodiment described above, the details thereof will not be repeated for the sake of brevity, in the case of this tenth embodiment, the fender 29 is fitted in a manner in which its inner end is fixed on the outer diametrical surface of the flange 1a of the outer member 1, and therefore, fitting of the fender 29 is easy to effect.Moreover, since the rim member 35 held in contact with the outer peripheral surface of the outer ring 1 is integrally fitted to the fender 29, there is no need to separately fit a sealing member such as a rim member to the fender 29, and a sealing member including the rim member 35 is fitted by fitting the fender 29, so that the work of fitting the sealing member is eliminated.

[0114] Also, in this tenth embodiment, since a front prominent shape of the vehicle mounting flange 1a of the outer ring 1 is designed to have line symmetry with respect to the line segment perpendicular to the bearing axis O or a point symmetry above the bearing axis O, the shape of the outer ring 1, which is a stationary member, is simplified, and therefore the temperature distribution caused by complications in the shape of the outer ring 1 and the variation in the expansion-contraction amount can be reduced. Accordingly, the influences caused by the temperature distribution in the outer ring and the variation in the expansion-contraction amount are sufficiently reduced to allow the sensor units 20A to 20D to detect the strain amount resulting from the load. Even if the front prominent shape of the flange 1a of the outer member 1 is designed to have Fig. 31 shown to be round, the attachment of the mudguard 29 on the outer diametrical surface can be easily achieved.

[0115] Fig. 34 and Fig. 35 illustrate an eleventh embodiment of the present invention. The sensor-equipped bearing assembly of a wheel support designed according to this eleventh embodiment is similar to that described with respect to Fig. 30 to 33 shown and described in connection with the tenth embodiment described above, but differs therefrom in that the outer peripheral surface of the cover portion 35a for the outer peripheral surface of the fender of the edge member 35 provided at the outer end of the fender 29 is shown as an inclined surface widening outwardly toward the outer side, as best shown in Fig. 35 in an enlarged sectional view. Other structural features than those described above are similar to those shown in the embodiment of the tenth embodiment described above. Fig. 30 to 33 can be used.

[0116] When the outer peripheral surface of the fender outer peripheral surface covering portion 35a of the rim member 35 is rendered to be the inclined surface widening outward toward the outer side, the flow of the muddy water and / or salt water into the area where the rim member 35 is held in contact with the outer peripheral surface of the outer member 1 can be avoided, and thus undesirable intrusion of the muddy water and / or salt water into the interior of the fender 29 can be prevented.

[0117] Fig. 36 and Fig. 37 illustrate a twelfth embodiment of the present invention. This sensor-equipped wheel support bearing assembly constructed according to the twelfth embodiment is similar to that constructed according to the previously described tenth embodiment described with reference to FIGS. Fig. 30 to 33, differs therefrom, however, in that the outer end of the protective plate 29 is made to extend beyond the outer ring 1 towards the outer side, and a non-contact sealing gap 39 in the form of a labyrinth seal is formed between its outer end and the inner element 2, which is the rotating element. The non-contact sealing gap 39 is a gap narrow enough to prevent an undesirable flow of water or the like when a relative rotation occurs between the inner element 2 and the outer ring 1, as described above. In the example shown, as in the Fig. 37 in an enlarged fragmentary view, the outer end of the fender 29 extends to a position near the side surface of the hub flange 9a in the inner member 2, which faces the inner side, and is then bent radially inward from the outer end of the fender 29 and toward the inner side to form a bent portion 29a, and is further bent from the tip of the bent portion 29a toward the inner diametrical side to form an inwardly bent portion 29b, and the rim member 35 is then integrally provided in this inwardly bent portion 29b. Structural features other than those described above are similar to those employed in the construction of the previously described tenth embodiment described with reference to FIG. Fig. 30 to 33 are shown and described.

[0118] As described above, when the non-contact seal gap 39 is formed between the outer end of the shroud 29 and the inner member 2, the seal between the outer end of the shroud 29 and the outer member 1 is reinforced by a double seal structure defined by the engagement of the rim member 35 with the outer peripheral surface of the outer ring 1 and the non-contact seal 39 formed between the outer end of the shroud 29 and the hub flange 9a of the inner member 2. Therefore, the seal on the outer side can be ensured, and the load detection can be accurately achieved, while securely avoiding any undesirable problems occurring in some or all of the sensors due to the influence of the external environment.

[0119] Fig. 38 and Fig. 39 illustrate a thirteenth embodiment of the present invention. The sensor-equipped bearing assembly of a wheel support constructed according to the thirteenth embodiment is similar to the sensor-equipped bearing assembly of a wheel support constructed according to the previously described twelfth embodiment described with reference to FIGS. Fig. 36 and Fig. 37, differs therefrom, however, in that the bent portion 29a at the outer end of the fender 29 is shown to represent a radially inwardly narrowed and inclined shape. Other structural features than those described above are similar to those described in the embodiment of the twelfth embodiment described with reference to Fig. 36 and Fig. 37 shown and described.

[0120] As described above, when the bent portion 29a at the outboard end of the fender 29 is rendered to have the radially inwardly narrowed and inclined shape, the muddy water and / or salt water entering the outboard end of the outer ring 1 through the non-contact seal gap 39 can be easily discharged to the outside through the non-contact seal gap 39 along the inclined surface of the outwardly oriented bent portion 29a, and therefore, the sealability at the outboard end of the fender 29 can be further enhanced.

[0121] Fig. 40 and Fig. 41 illustrate a fourteenth embodiment of the present invention. The sensor-equipped wheel support bearing assembly constructed according to the fourteenth embodiment is similar to the sensor-equipped wheel support bearing assembly according to the tenth embodiment described with reference to FIGS. Fig. 30 to 33, however, differs in that the edge element 35 provided at the outer end of the protective plate 29 is brought into contact with a surface of the inner element 2, which is the rotating element. More specifically, as shown in Fig. 41 in an enlarged fragmentary view, the outer end of the fender 29 extends toward the outer side beyond the outer ring 1, and the edge member 35 is held in contact with an inwardly oriented side surface of the hub flange 9a of the hub axle 9, which forms one of the component parts of the inner member 2. Other structural features than those described above are similar to those used in the embodiment of the tenth embodiment described with reference to FIG. Fig. 30 to 33 shown and described.

[0122] As described above, even if the rim member 35 provided at the outer end of the fender 29 is held in contact with the hub flange 9a of the inner member 2, undesirable intrusion of, for example, muddy water and / or salt water through the outer end of the fender 29 into the fender 29 can be reliably prevented, and therefore, any undesirable problem in some or all of the sensors under the influence of the external environment can be reliably prevented, allowing accurate load detection. Also, in such a case, since the outer end of the bearing space defined between the outer ring 1 and the inner member 2 is also sealed, it is possible to dispense with the outer sealing member 7.

[0123] Fig. Figure 42 illustrates a sectional view showing a general overview of a bearing support assembly installed in an internal wheel motor using the sensor-equipped wheel support bearing assembly described with particular reference to Figure 42. Fig. 30 to 33 in connection with the tenth embodiment of the present invention. The wheel support bearing assembly incorporated in an in-wheel motor is of a structure in which the sensor-equipped wheel support bearing assembly A for rotatably supporting a hub for a vehicle drive wheel, an electrically driven motor B as a rotational drive source, a reduction gear C for reducing the rotation of the electrically driven motor B and then transmitting it to the hub, and a brake D for applying a braking force to the hub, all of which are arranged on a center axis of the vehicle drive wheel 40. The electrically driven motor B is of a radial gap type in which a radial gap is provided between a stator 42 fixed to a tubular casing 41 and a rotor 44 fitted to an output shaft 43.The reduction gear C is designed as a cycloidal reducer.

[0124] As described above, when the sensor-equipped wheel support bearing assembly A designed according to the teachings of the present invention is used as a wheel support bearing for the wheel support bearing assembly built into the internal wheel motor, it is possible to reproduce it as an internal wheel motor-built wheel support bearing assembly of the type in which any undesirable problem that may occur with some or all of the sensors due to the influence of the external environment can be avoided in order to accurately detect the load acting on the wheel support bearing assembly or the base of a wheel tire contact over a longer period of time. It should be noted that although in Fig. 42 shows the sensor-equipped bearing arrangement of a wheel support according to the tenth embodiment of the present invention with reference to the Fig. 30 to 33, the present invention is not necessarily limited thereto and can be equally applied even if the sensor-equipped wheel support bearing assembly constructed according to any other of the remaining embodiments of the present invention is applicable, and even in such a case, effects similar to those described above can be obtained.

[0125] It should be noted that although in describing each of the foregoing embodiments of the present invention, the present invention has been shown and described as applied to the wheel support bearing assembly of the third generation type, the present invention can equally be applied to the wheel support bearing assembly of the first or second generation type in which the bearing portion and the hub are separate components, or to the wheel support bearing assembly of the fourth generation type in which a portion of the inner member is constructed from an outer ring of a constant velocity joint. Also, the sensor-equipped wheel support bearing assembly can be applied to a wheel support bearing assembly for supporting a vehicle-driven wheel, and also to the wheel support bearing assembly of any generation type in which tapered rollers are used.In such a case, the sensor units are provided on the outer circumference of the inner element.

[0126] Below, some forms are described alongside each of the embodiments of the present invention. [Mode 1]

[0127] The sensor-equipped wheel support bearing assembly according to the first mode is a wheel support bearing assembly for rotatably supporting a vehicle wheel with respect to a body, which includes an outer ring having an inner periphery formed with a plurality of rolling surfaces, an inner ring having an outer periphery formed with rolling surfaces held in opposing relationship with the above-described rolling surfaces, and a plurality of rows of rolling elements disposed between the rolling surfaces of the outer ring and the rolling surfaces of the inner member, in which a vehicle mounting flange to be fitted to a steering knuckle is provided in an outer periphery of the outer member;wherein one or more sensor units comprising a strain-generating element having two or more contact-fixing segments adapted to be fixed to the outer circumference of the outer ring in contact therewith, and a sensor adapted to the strain-generating element and operative to detect a strain induced in the strain-generating element are provided at respective positions crossing a line segment extending through a center of each of the rolling elements on the outer circumference of the outer ring on an outside side in a direction required to form a contact angle of the rolling elements, or at respective positions adjacent to such positions;wherein a front highlighted shape of the flange is selected to have a line symmetry with respect to a line segment perpendicular to a bearing axis or a point symmetry above the bearing axis; [Mode 2]

[0128] The sensor-equipped wheel support bearing assembly according to the second mode is a wheel support bearing assembly for rotatably supporting a vehicle wheel relative to a vehicle body, which includes an outer ring having an inner periphery formed with a plurality of rolling surfaces, an inner member having an outer periphery formed with rolling surfaces held in opposing contact with the above-described rolling surfaces, and a plurality of rows of rolling elements disposed between the rolling surfaces of the outer ring and the rolling surfaces of the inner member, in which a radially inwardly depressed portion, the outer periphery of which is formed with an externally threaded portion for attachment to a steering knuckle, is provided at an inner end of the outer ring;wherein one or more sensor units comprising a strain-generating element having two or more contact-fixing segments adapted to be fixed in contact with a portion of the outer circumference of the outer ring on an outer side of the radially inwardly pressed portion of the outer ring, and a sensor adapted to the strain-generating element and operable to detect a strain induced in the strain-generating element are provided at respective positions crossing a line segment extending through a center of each of the rolling elements on the outer circumference of the outer ring on an outer side in a direction required to form a contact angle of the rolling elements, or at respective positions adjacent to such positions;and wherein the external thread portion of the radially inwardly pressed portion threadably engages an internal thread portion provided in an inner periphery of the steering knuckle to fix the outer ring to the steering knuckle; [Mode 3]

[0129] The sensor-equipped wheel support bearing assembly according to the second mode is a wheel support bearing assembly for rotatably supporting a vehicle wheel relative to a vehicle body, which includes an outer member having an inner periphery formed with a plurality of rolling surfaces, an inner member having an outer periphery formed with rolling surfaces held in opposing relationship with the above-described rolling surfaces, and a plurality of rows of rolling elements disposed between the rolling surfaces of the outer member and the rolling surfaces of the inner member, in which a vehicle mounting flange adapted to be fitted to a steering knuckle is provided on an outer periphery of the outer member or the inner member, which is a stationary member;wherein a plurality of sensor units are fixed to an outer periphery of the stationary member for detecting a load; wherein said plurality of sensor units are covered with a tubular shroud surrounding the outer periphery of the stationary member; wherein an outer end of the shroud is fixed to an outer peripheral surface of the stationary member; and wherein a rim member made of an annular elastic member is held along an open edge of an inner end of the shroud in contact with an outwardly oriented side surface of the flange or the outer peripheral surface of the stationary member. [Mode 4]

[0130] The sensor-equipped wheel support bearing assembly according to the second mode is a wheel support bearing assembly for rotatably supporting a vehicle wheel relative to a vehicle body, which includes an outer member having an inner periphery formed with a plurality of rolling surfaces, an inner member having an outer periphery formed with rolling surfaces held in opposing relationship with the above-described rolling surfaces, and a plurality of rows of rolling elements disposed between the rolling surfaces of the outer member and the rolling surfaces of the inner member, in which a vehicle mounting flange adapted to be fitted to a steering knuckle is provided on an outer periphery of the outer member or the inner member, which is a stationary member,wherein a plurality of sensor units are attached to an outer periphery of the stationary member for detecting a load, said plurality of sensor units being covered with a tubular protective sheet surrounding the outer periphery of the stationary member, an inner end of the protective sheet being attached to an outer diametrical surface of the stationary member, and a rim member made of an annular elastic member and provided along an open edge of an outer end of the protective sheet being held in contact with an outer peripheral surface of the stationary member or a surface of the outer member or the inner member, which is a rotating member.

[0131] Although the present invention has been fully described in connection with the embodiments with reference to the accompanying drawings, which are used for illustrative purposes only, a person skilled in the art will recognize various changes and modifications within the obvious scope upon reading the above specification of the present invention. Accordingly, such changes and modifications are to be interpreted as included herein unless they depart from the scope of the present invention as defined by the appended claims. [Reference symbol] 1 outer ring (outer element) 1a Body mounting flange 1aa curved section area 1d radially inward pressed area 1da external thread area 2 inner element 3.4 rolling surfaces 5 rolling element 20,20a-20d sensor unit 21 strain-generating element 21a Contact fixing segment 22,22a,22b strain sensor 29 mudguard 30 flexible substrate 31 signal processing IC 32 signal cables 33 Sensor arrangement 35 edge element 35a Covering area for the outer peripheral surface of the mudguard 36 pull-through hole 37 Sealing material 38 surface-treated layer 39 contactless sealing gap

Claims

[1] A wheel support bearing arrangement for rotatably supporting a vehicle wheel relative to a vehicle body, comprising: - an outer member (1) having an inner circumference formed with a plurality of rolling surfaces (3, 4); - an inner member (2) having an outer periphery formed with rolling surfaces (3, 4) held in opposing relationship with the above-described rolling surfaces (3, 4); - a plurality of rows of rolling elements (5) arranged between the rolling surface (3) of the outer element (1) and the rolling surface (4) of the inner element (2); - a body connection flange (1a) to be attached to a steering knuckle provided on an outer periphery of the outer member; and - one or more sensor units (20, 20a, 20d) comprising a strain generating element (21) having two or more contact fixing segments (21a) adapted for fixing to the outer periphery of the outer member (1) by contact therewith, and a sensor fixed to the strain generating element (21) and operable to detect a strain induced in the strain generating element (21) provided at an arcuate portion (1aa) formed to extend from a bottom end of an outwardly facing side surface of the flange toward the outer periphery of the outer member (1), or at an outer peripheral surface portion of the outer member (1) adjacent to the arcuate portion (1aa) on an outer side,wherein the flange has a front highlighted shape of line symmetry with respect to a line segment perpendicular to a bearing axis or a point of symmetry above the bearing axis, - wherein the one or more sensor units (20, 20a, 20d) are surrounded by a tubular protective plate (29) with an edge element (35) made of an elastic material, which surrounds an outer periphery of the outer element (1). [2] A wheel support bearing assembly with sensor according to claim 1, wherein each of said one or more sensor units (20, 20a, 20d) is provided at a position at which a line segment including a center of each of said rolling elements (5) on the outer side and defining a contact angle of said rolling elements (5) crosses the outer periphery of said outer member (1) or a position adjacent thereto. [3] A wheel support bearing assembly with sensor according to claim 1, wherein a plurality of said sensor units (20, 20a, 20d) are used, and said sensor units (20, 20a, 20d) are provided at an equal pitch in a circumferential direction of the outer periphery of said outer member (1). [4] A wheel support bearing assembly with sensor according to claim 1, wherein the sensor unit (20, 20a, 20d) is provided in an outer peripheral surface area of ​​the outer member (1) within a range spaced within 5 mm from a terminating end of the arcuate portion part (1aa) in the outwardly oriented side surface of the flange. [5] A wheel support bearing assembly with sensor according to claim 1, wherein an outer end of the fender (29) is fixed on the outer peripheral surface of the outer member (1), and the rim member (35) provided along an open edge of an inner end of the flange is held in contact with the outwardly facing side surface of the flange or the outer peripheral surface of the outer member (1). [6] A wheel support bearing assembly with sensor according to claim 1, wherein an inner end of the fender (29) is fixed on the outer peripheral surface of the outer member (1), and the rim member (35) provided along an open edge of an outer end of the flange is held in contact with the outer peripheral surface of the outer member (1) or a surface of the inner member (2). [7] A wheel support bearing assembly with sensor according to claim 1, further comprising a sensor assembly (33) fixed to the outer peripheral surface of the outer member (1) in a coaxial manner with the outer member (1) and surrounded by the fender (29), the sensor assembly (33) being made of electronic component parts connected in a ring shape including the sensor unit, a signal processing IC (31) for processing an output signal of the sensor unit, and a signal cable (32) for guiding the processed output signal to the outside of a bearing unit. [8] A wheel support bearing assembly with a sensor according to claim 1, wherein the sensor unit (20, 20a, 20d) is fitted to a flexible substrate (30), and further comprises a sensor assembly (33) fitted to the outer peripheral surface of the outer member (1) in a coaxial manner with the outer member (1) and surrounded by a guard plate (29), the sensor assembly (33) being made of electronic component parts connected in a ring shape including the sensor unit (20, 20a, 20d), a signal processing IC (31) for processing an output signal of the sensor unit (20, 20a, 20d), and a signal cable (32) for conducting the processed output signal to the outside of a bearing unit, the signal processing IC (31) and the signal cable (32) being fitted to the flexible substrate (30). [9] A wheel support bearing assembly with sensor according to claim 1, wherein the outer end of the guard plate (29) extends toward the outer side beyond the outer member (1), a non-contact sealing gap (39) being formed between the outer end thereof and the inner member (2). [10] A wheel support bearing assembly with sensor according to claim 5, wherein the edge member (35) has a shape that widens outwardly toward the inner side. [11] A wheel support bearing assembly with sensor according to claim 6, wherein the edge member (35) has a shape which decreases diametrically towards the outer side and is held in contact with the outer peripheral surface of the outer member (1). [12] A wheel support bearing assembly with sensor according to claim 6, wherein the edge member (35) has a portion extending to a portion of the outer peripheral surface of the fender (29) to define a cover portion (35a) of the outer peripheral surface of the fender (29). [13] A wheel support bearing assembly with sensor according to claim 6, wherein the inner member (2) has a hub flange for mounting a vehicle wheel and the edge member (35) is held in contact with the inwardly oriented side surface of the hub flange. [14] A wheel support bearing assembly with sensor according to claim 1, wherein four of the sensor units (20, 20a, 20d) are used, the four sensor units (20, 20a, 20d) being arranged at an equal interval on upper, lower, left and right surface portions of the outer peripheral surface of the outer member (1) which assumes upper, lower, left and right positions with respect to a contact of the vehicle tire with the ground surface at a phase difference of 90 degrees in a circumferential direction. [15] A wheel support bearing assembly with a sensor according to claim 1, wherein the sensor unit (20, 20a, 20d) comprises three or more contact fixing segments (21a) and two sensors, the two sensors being respectively fitted between the adjacent first and second contact fixing segments (21a) and between the adjacent second and third contact fixing segments (21a), the distance between the adjacent contact fixing segment (21a) or the adjacent sensors in the circumferential direction of the outer member (1) being selected to be (1 / 2+n) times a pitch of the arrangement of the rolling elements (5), where n represents an integer, and a load is estimated from the sum of the respective output signals of the two sensors used as an average value.

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