KR20220062219A - Bearing assembly that detects self-transmitted forces and torques - Google Patents

Abstract

The present invention relates to a bearing assembly which self-detects transmitted force or torque, and to the bearing assembly which connects a road wheel to a suspension system element on a vehicle body. The bearing assembly comprises a hub to which the road wheel is attached and a housing which is attached to the suspension system element. The hub rotates on rolling elements, which are arranged in two rows, one by one between opposite-side raceways on the hub and the housing, inside the housing. The rolling elements give a slight curve on the housing, and the curve is detected by a strain sensor attached on the housing. The present invention relates to the bearing assembly having the strain sensor that generates an electric signal for calculating a weight of the mechanical system in which a bearing is combined.

Description

Bearing assembly that detects self-transmitted forces and torques

The present invention relates, generally speaking, to bearings, and more particularly to providing electrical signals for use by devices for detecting and controlling vehicle dynamics based on calculated tire patch loads; Or to a bearing assembly that detects the force and torque transmitted by itself, in order to measure the general stress, strain and load applied to the bearing.

There are many applications where the load and the type of load applied to the bearing during operation can provide sufficient information about the bearing and the objects attached to it. One such application is the automobile industry, in which such load information in the form of electrical signals is extremely important for proper application of vehicle dynamic control ('VDC') systems.

Another application is in the steel mill industry, where electronic processing and control are used to regulate the speed and load of the rollers during the rolling process. Another application is in the machine tool industry, where programmable controllers and processors control the speed of spindles in milling, cutting and drilling machines. detect and control

The automotive industry continues to develop electronic devices that help drivers maintain control of their vehicle through various combinations of braking action and continuous suspension adjustments, but as these systems become more sophisticated, the pressure applied from the tire contact patch increases. We need a reliable input signal that represents a sufficient load range to indicate the load.

Similarly, the rolling mill and machine tool industries use several forms of process control that require the detection of loads on bearings. Specifically, rolling mills require bearing feedback regarding an indication of belt slipping on the rollers or an indication that a particular set of rollers is experiencing a higher load. Computer-controlled machine tools need to detect the load being experienced by the bearings supporting the spindle in order to assess whether the cutting and drilling tool has become dull, or whether the cutting or drilling speed exceeds set limits for proper machining operations. there is.

The bearing assembly (A) is mounted on some rotating shaft fixture, after which the bearing sensors are used to provide electrical signals indicative of the circumferential, circumferential-axial, axial torque and shear strain on the bearing. Applications that require such information are process control of rolling mills and process control of machine tools. For those skilled in the art of bearing design and bearing use, it is possible to detect these bearing loads relative to the loads they bear and provide an electrical signal.

The bearing assemblies that detect self-transmitted forces and torques of the present invention can detect these bearing loads relative to the loads they bear and provide an electrical signal.

It is also possible to use strain sensors to use electrical signals in a form and mode that can be used by automotive devices or other electronic devices in the rolling mill industry or machine tool industry.

1 is a perspective view of a road wheel showing several forces and torques acting on the road wheel;
2 is a cross-sectional view of a bearing assembly constructed in accordance with the present invention and embodying the present invention;
3 is a plan view of one of the sensor modules for the bearing assembly;
4 is a plan view of a sensor of the sensor module of FIG. 3 ;
5 is a perspective view of a housing for a bearing assembly;
6 is a cross-sectional view of a housing for a modified bearing assembly;
Fig. 7 is an exploded view showing the sensor module of the modified bearing assembly spread out in a single plane. Fig. 8 is a cross-sectional view of a housing for another modified bearing assembly.

A bearing assembly that detects its own transmitted forces and torques experiences several forces and torques as the road wheel W (FIG. 1), which supports the vehicle on the road surface, rolls along the road surface. First, in general, there is a vertical force (Fv) representing a certain inertia force generated by braking and irregularity of the road surface and the weight of the vehicle. The road wheel W also experiences a horizontal force Fh which generally acts in the direction in which the road wheel travels. Also, there is a thrust load Ft, which is a force directed in the axial direction, which is the direction of the rotation axis X. In addition, there is a vertical torque Tv, that is, a torque vertically penetrating the road wheel W, sometimes called a steering torque. Finally, there is a horizontal torque Th, sometimes called an overturning moment, which acts about an axis horizontally penetrating the road wheel W in the traveling direction of the road wheel W. The road wheel W has a rim 2 and a tire 4 mounted on the rim 2 . The tire 4 is in contact with the road surface along a tire contact patch 6 , in which the tire 4 experiences a force F and a torque T. The magnitudes of force and torque represent the conditions at the tire contact patch 6 and, when evaluated in real time along with other conditions, give an excellent indication of the vehicle's ability to keep the vehicle under control or, on the other hand, to get out of control. to provide.

The road wheel W is connected to a vehicle suspension system element C ( FIG. 2 ) in a bearing assembly A, which bearing assembly transfers the load between the road wheel W and the suspension system element C while the road wheel W ) to rotate around the axis (X). Typically, the suspension system element C is a steering knuckle. The bearing assembly (A) comprises a hub (12) to which the rod wheel (W) is attached, a housing (14) secured to a suspension system element (C), and disposed between the hub (12) and the housing (14) to include the hub ( 12 has a bearing 16 that allows it to rotate with minimal friction on the housing 14 . To receive the housing 14 , the suspension system element C is provided with a through bore 18 and a machined end face 20 . In most cases, housing 14 partially fits through bore 18 and abuts end face 20 . Bearing 16 is received within housing 14 . The hub 12 extends into the bearing 16 and is held in the axial and radial directions.

More specifically, the hub 12 includes a flange 26 and a hollow spindle 28 protruding from the flange 26 at a shoulder 30 disposed on the rear surface of the flange 26 . A lug bolt 32 is fastened to the flange 26 from the outside of the shoulder 30, and these lug bolts protrude from the other side in the axial direction and pass through the rim 2 of the road wheel W. . A lug nut 34 is screwed on the lug bolt 32 outside the road wheel W to fix the road wheel W to the hub 12 .

Spindle 28 is upset at its distal end from flange 26 , ie is deformed outwardly to provide a shaped end 36 which is perpendicular to axis X and is provided towards shoulder 30 . It has a supporting surface 38 which is A bearing 16 is sandwiched between the shoulder 30 on the flange 26 and the bearing surface 38 of the forming end 36 .

Bearing 16 includes an inner race in the form of two cones 40 fitted around spindle 28 , with an interference fit between each cone 40 and spindle 28 . . Each cone 40 has a tapered raceway 42 provided outwardly from the axis X, a thrust rib 44 at the large end of this raceway 42, and a thrust rib ( 44) has a back surface 46 formed at right angles to the axis X on its end. The inner cone 40 is somewhat longer than the outer cone 40 because of the cylindrical cone extension 48 that projects past the small end of the raceway 42 . The cone extension 48 may act as a seat for a target wheel as detected by a speed sensor in the housing 14 . The inner cone 40 abuts the small end of the outer cone 40 along the spindle 28 at its cone extension 48 , ie the two cones 40 contact at their front faces. . The back face 46 of the outer cone 40 is in contact with the shoulder 30 along the flange 26 , while the back 46 of the inner cone 40 has an end face on the forming end 36 ( 38) is in contact with

In addition to the two cones 40 , the bearing 16 comprises tapered rollers 54 arranged in two rows, with a separate row around each cone 40 . In practice, rollers 54 extend around raceway 42 of cone 40 , with primarily line contact between the tapered sides of roller 54 and raceway 42 . The large end face of the roller 54 is supported on the thrust ribs 46 .

The rollers 54 of each row are almost at the top, meaning that the envelope on which the tapered sides of these rollers are disposed have vertices disposed at a common point along the axis X. Each row of rollers 54 has a cage 56 to maintain proper spacing between the rollers 54 within that row.

The housing 14 encloses the spindle 28 as well as two cones 40 and two rows of rollers 54 . Its housing forms part of the bearing 16 in that it has tapered raceways 58 which are provided in an inward direction towards the axis X. In that sense, the housing 14 constitutes the outer race of the bearing 16 . Raceways 58 on housing 14 taper downwardly towards cylindrical intervening surfaces 59 that separate them. These rollers 54 are also laid along the raceway 58 of the housing 14, and a line contact is mainly made between the raceway 58 and the tapered side of the roller 54. The raceways 58 open at their large ends into short end bores 60 , in which the thrust ribs 44 of the two cones 40 are arranged. Therefore, each end of the bearing 16 has an annular space, which space exists between the thrust rib 44 of the bearing end and the major surface of the end bore 60 .

The housing 14 has a generally cylindrical outer surface 62 and a triangular or rectangular flange 64 protruding from the outer surface 62 midway between the end faces of the outer surface. The diameter of the outer surface 62 in the region behind the flange 64 is slightly smaller than the diameter of the through bore 18 of the suspension system element C . This part of the housing 14 fits into the through bore 18 with a slight gap, while the back of the flange 64 bears on the end face 24 of the suspension system element C. The housing 14 is rigidly secured by bolts 66 that pass through the suspension system element C and screw into a flange 64 on the housing 14 .

The annular space at the end of the bearing 16 is sealed with a seal 68 that fits within the end bore 60 of the housing 14 and around the thrust rib 44 of the cone 40 . U.S. Patent No. 5,022,659 discloses suitable seals at both points.

The molded end 36 uses the assembly (A). However, the hub 12 does not always have a shaped end 36 . Initially, the spindle 28 of the hub 12 extends as a cylindrical surface from the shoulder 30 to the always free end. The two cones 40, as supplements to the rollers 54, and as a housing 14 sandwiched between the two rows of rollers 15, are mounted on the cylindrical surface of the spindle 54 to the rear surface of the outer cone 40 ( Proceed until 46 ) strikes shoulder 30 at the other end of spindle 28 . When the cone 40 is so positioned, a portion of the spindle 28 projects beyond the back surface of the inner cone 40 . This part is transformed as a molded end 36 . PCT application GB 98 /01823 (International Publication No. WO98/58762) upsets the initially extended end of the spindle 28 and converts it to an integrally formed end 36 used in the actual overall assembly A discloses a rotational molding process.

Other means may also secure the two cones 40 on the spindle 28 . For example, the end of the spindle 28 may have a helix and a nut fastened to the helix and rotated against the back surface 46 of the inner cone 40 .

When the assembly A is so used, the bearing 16 remains with a slight preload applied. In practice, the spacing between the inner raceways 42 of the cones 40 determines the setting of the bearings 16, and the rotational forming process that results in the forming end 46 causes the cone extensions 48 on the inner cone to The spacing depends on the length of the cone extension 48 of the inner cone 40, as long as it moves the inner cone 40 in the direction of the outer cone 40 with sufficient force to abut the small end of the cone. . A nut screwed onto the spindle 28 and rotated so as to be in tight contact with the rear surface 46 of the inner cone 40 has the same effect.

The forces Fv, Fh, Ft and torques Tv, Th acting on the road wheel W reflect the state in the tire contact patch 6 . For example, if the external thrust load Ft is zero, this reflects the linear running, indicating that it is somewhat larger than the preload in the bearing 16 . On the other hand, an unbalanced, larger thrust load Ft in one direction greater than the other would reflect a curved ride or perhaps a significant inclination to one side of the vehicle. The increase in the vertical force Fv reflects the action of the brake or curved driving if the road wheel W is the front wheel of the vehicle.

The forces Fv, Fh, Ft and torques Tv, Th experienced by the road wheel W are transmitted through the bearing assembly A to the suspension system element C, so that the bearing assembly A also ) and torque (T). These forces (F) and torques (F) are self-evident as a slight expansion and contraction of the housing, which is slightly outwardly from both raceways (58) on the outer surface (62) of the housing (14). It is detected by the sensor module M (Fig. 5) attached to the In effect, tapered roller 54 transfers force F and torque T from cone 40 to housing 14 , which expands and contracts to bearing 18 as it rolls along raceway 58 . give action This expansion and contraction is transmitted to and along the outer surface 62 to the sensor module M.

In one embodiment, each sensor module M includes a strain gauge 70 consisting essentially of a carrier matrix 72 and two foil resistance elements 74 and 76 . including (FIGS. 3 and 4). Although the description of this embodiment describes the use of a bonded resistance strain gauge sensor that operates by changing the resistance value, a mechanical sensor, a photoelectric sensor, an optical sensor, a capacitive sensor, an inductive sensor, and a semiconductor sensor It should be noted that other types of strain sensors such as However, in this embodiment, the carrier matrix 72 is formed of a suitable polymer, such as polyimide, which can itself expand and contract with the housing 14 . The carrier matrix is adhered to the outer surface of the housing 14 by means of a suitable adhesive. Each foil resistance element 74 , 76 is formed from a suitable metal foil, such as a constantan foil, which is bonded to a carrier matrix 72 to undergo the same expansion and contraction as the carrier matrix 72 . . Each foil resistance element 74 , 76 has several parallel legs 78 and an end loop 80 connecting the ends of adjacent legs 78 . Foil resistive elements 74 , 76 are both on carrier matrix 72 but electrically insulated from each other. Moreover, the legs 78 of the foil resistance element 74 are oriented at 90° with respect to the legs 78 of the foil resistance element 76 . The resistance of each leg 78 varies as it undergoes the expansion and contraction experienced by the carrier matrix 72, and the resistance of each foil resistive element 74, 76 varies as long as multiple legs 78 are connected in series. Even greater resistance changes. This carrier matrix 72 electrically insulates the foil resistive elements 74, 76 from the metal housing 14, but prevents slight expansion and contraction of the housing 14 to the legs 78 of the foil resistive elements 74, 76. transmit

Each sensor module M includes, in addition to its sensor 70 , a temperature compensator 84 and a terminal block 86 . The temperature compensator 84 must operate at the same temperature as the sensor 70 , which is why it must be placed on the housing 14 adjacent to the sensor 70 , even on the carrier matrix 72 of the sensor 70 . . In this regard, the resistance of the foil resistive elements 74 , 76 varies not only with the expansion and contraction of the carrier matrix 72 , but also with temperature. A temperature compensator 84 is coupled to the foil resistive elements 74, 76 through a bridge circuit or through a processor to compensate for or offset changes in the resistance of the foil resistive elements 74, 76 due to temperature changes. ) do. Therefore, the signal obtained from the foil resistive elements 74 and 76 reflects only the change in strain. Terminal block 86 houses terminals 88 to which, via leads, tabs 82 on foil resistive elements 74 and 76 are connected, likewise a temperature compensator 84 . ) is connected. Terminal 88 is again connected to a processor that evaluates and processes the signals generated by foil resistive elements 74 , 76 and temperature compensator 84 .

Four sensor modules M are attached to the outer surface 62 of the housing 14 in a radially outward direction from the outer raceway 58, and these four sensor modules are arranged at intervals of 90° (FIG. 5). ), one is provided with a sensor 70 on the upper surface of the outer surface 62, the other is provided with a sensor 70 on the lower surface of the outer surface 62, and the other two are provided with a sensor 70 on the lower surface of the outer surface 62. A sensor 70 is provided on the side of the The remaining four sensor modules M are also attached to the outer surface 62 , but they are disposed radially outward of the inner raceway 58 . They are also spaced 90° apart, with their sensors 70 on the top, bottom and sides of the outer surface 62 . In other words, these sensors 70 are arranged in two rows, the sensors in each row are arranged at 0°, 90°, 180°, and 270°, and 0° is the upper plane center. For each sensor 70 of the eight modules M, the leg 78 of the foil resistive element 74 for that sensor 70 extends in the circumferential direction, while the leg 78 of the foil resistive element 76 ) extends in the axial direction.

When the road wheel (W) rolls on the road surface and supports with it the suspension system element (C) - and the entire vehicle body of which element (C) is a part - the spindle 28 of the hub 12 connects to the housing 14 ) rotates within The cone 40 of the bearing 16 rotates as well as it is fitted on the spindle 28 with an interference fit. The outer row of tapered rollers 54 roll along the raceway 42 of the outer cone 40 and the outer raceway 58 of the housing 14 . The inner row of tapered rollers 54 roll along the raceway 42 of the inner cone 40 and the inner raceway 58 of the housing 16 . As these rollers 54 roll between the individual raceways 42 , 58 , these rollers transfer radial loads between the cone 40 and the housing 14 . A radial load applied by some roller 54 against the outer raceway 58 on which it rolls causes the housing 14 to bend slightly, which curvature exists in the raceway 58 but causes the housing 14 to bend. a slightly smaller axial direction radially outwardly, slightly circumferentially, from the line of contact between the raceway 58 and the rollers 54 of the outer surface 62 itself through prove age. Therefore, whenever the loaded roller 58 passes between the sensor 70 and the axis X, the flex that occurs along the raceway 58 is transmitted from the sensor 70 to the outer surface 62. Extending the parallel legs 78 of the foil resistive element 74 of the sensor 70 increases the resistance of the foil resistive element 76 . The magnitude of the change in resistance is dictated by the load, because a roller supported on the raceway 58 with a greater force imparts greater flex than a roller supported with a lesser force. By comparing the flexure reflected by the signal from the sensor 70 - thus the load on the rollers - the condition in the tire patch 6 can be checked in real time.

The modified bearing assembly B (FIG. 6) is identical to the bearing assembly A in all respects except for the position of the sensor module M. In the bearing assembly (B), eight sensor modules (M) are attached to the flange (64) of the housing (16) adjacent the outer surface (62), opposite the outer surface of the flange (64), a single unit arranged in columns. The four sensor modules M have sensors 70 arranged at intervals of 90° around a flange 64 , one of these sensors 70 on the upper surface of the flange 64 and the other on the flange 64 . 64), the other two are provided on the side of the flange 64, ie these sensors 70 are arranged at 0°, 90°, 180° and 270° ( FIG. 7 ). These sensors 70 have legs 78 of foil resistive elements 74 extending in a circumferential direction, these legs 78 being parallel to the major axis of the sensor 70 .

With respect to the load wheel W on the hub 12 driven on the spindle 28 , the remaining four sensor modules M have foil resistive elements 74 , 76 for the sensor 70 oriented at 45° with respect to the circumferential direction. ) of the legs 78 are mounted. One of these additional sensor modules M has a sensor 70 arranged at 65° rearward of the sensor 70 on the upper surface of the flange 64 , ie 65° rearward of the upper surface center ( FIG. 7 ). The other of the four remaining sensor modules 70 has a sensor 70 disposed at 25° forward of the top center, while the other has a sensor 70 disposed at 65° forward of the top center . Another sensor module is provided with the sensor 70 at 155° forward from the center of the upper surface. The four remaining sensors, ie those having a leg 78 of foil resistive elements at 45° with respect to the circumferential direction, measure the shear strain in the housing 14 .

The other modified bearing assembly C ( FIG. 8 ) is also similar to the bearing assembly A in all respects except for the position of the sensors 70 for the eight sensor modules M. The bearing assembly (C) has a sensor module (M) disposed along and attached to an intervening surface (59) between the two raceways (58) of the housing (14). The four sensor modules M have sensors 70 disposed at 0°, 90°, 180° and 270° around the intervening surface 59 , the uppermost surface of which is 0°. These sensors 70 have a circumferentially extending leg 78 of their foil resistive element 74 and an axially extending leg 78 of the foil resistive element 76 . The remaining four sensor modules M have their sensors 70 disposed at 25°, 65°, 155° and 295° from the center of the upper plane, measured around the front. The legs 78 of the foil resistive elements 74 , 76 of the remaining sensor 70 are oriented at 45° with respect to the circumferential direction and likewise at 45° with respect to the axial direction. Briefly, the position of the sensor 70 disposed along the intervening surface 59 corresponds to the position of the sensor 70 disposed along the flange 64 of the bearing assembly B, basically, the sensor 70 ) with respect to the orientation of the foil resistance elements 74 and 76.

Another embodiment is similar to bearing assembly (A) in all respects, except that there is no road wheel (W), rim (2) or hub (12). Instead, the bearing assembly (A) is mounted on some rotating shaft fixture, after which the bearing sensors are used to provide electrical signals indicative of overall circumferential, circumferential-axial, axial torque and shear strain on the bearing. Applications that require such information are process control of rolling mills and process control of machine tools. It is clear to those skilled in the art of bearing design and bearing use that, with respect to the loads they bear, there are many other fields that require the use of bearings that can detect these bearing loads and provide an electrical signal.

Claims (6)

A bearing assembly that detects forces and torques transmitted therein, comprising: an inner race outwardly from an axis and having first and second inner raceways angled in opposite directions with respect to the axis; first and second outer surfaces surrounding the first and second inner raceways and having circumferential and generally axially oriented surfaces, respectively inwardly facing the first and second inner raceways and surrounding the first and second inner raceways a housing comprising a raceway, wherein the outer raceways are also inclined in opposite directions with respect to the axis, the inner race rotates with minimal friction within the outer race, and wherein the individual rolling elements are arranged along the raceway a first rolling element arranged in-line between the first raceways and in contact with the first raceways and a first rolling element arranged in-line between the second raceways and the second a second rolling element in contact with the raceways, attached at 0°, 90°, 180° and 270° respectively to a circumferential reference, parallel to the circumferential and generally axially oriented surface of the housing; first, second, third and fourth strain sensors oriented to detect circumferential strain and on the circumferentially and generally axially oriented surface of the housing between the first and second sensors and a fifth strain sensor attached thereto and oriented to detect strain in an oblique direction with respect to the circumferential direction. 2. The second sensor of claim 1, wherein a second sensor is attached to the circumferentially and generally axially oriented surface of the housing between the second and third sensors and is oriented to detect strain in a direction oblique with respect to the circumferential direction. 6 A bearing assembly for detecting self-transmitted forces and torques, characterized in that it promotes rotation about an axis while transmitting a radially directed force, further comprising a strain sensor. 3. The seventh of claim 2, wherein the seventh sensor is attached to the circumferentially and generally axially oriented surface of the housing between the fourth and first sensor and is oriented to detect strain in a direction oblique with respect to the circumferential direction. A bearing assembly for detecting a self-transmitted force and torque that promotes rotation about an axis while transmitting a radially directed force, further comprising a strain sensor. 4. The second sensor of claim 3, attached to the circumferentially and generally axially oriented surface of the housing between the first and second sensors and oriented to detect strain in a direction oblique with respect to the circumferential direction. 8 A bearing assembly for detecting self-transmitted forces and torques, further comprising a strain sensor, said self-transmitted force and torque facilitating rotation about an axis while transmitting a radially directed force. 5. The radially oriented according to claim 4, wherein the fifth, sixth, seventh and eighth sensors are respectively disposed at 25°, 65°, 155° and 295° from the circumferential reference. A self-transmitted force and torque-sensing bearing assembly, characterized in that it promotes rotation about an axis while transmitting the force. The bearing assembly of claim 1, wherein the first, second, third and fourth sensors also detect axial strain.

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