Wheel speed sensor

A wheel speed sensor includes an electromagnetic sensor having an electromagnetic sensor head disposed at a distal end thereof and a flange acting as a sensor support. The electromagnetic sensor head includes a magnet and an integrated circuit for sensing movement of a tone ring formed of magnetic attractive material. A sensor interface disposed at the distal end of the electromagnetic sensor is mechanically secured to a flange interface of the flange. The sensor interface can include outwardly projecting opposing tabs on opposing sides of the electromagnetic sensor head that are received by opposing apertures in parallel, spaced projecting arms that form the flange interface. In another arrangement, the sensor is inserted into an opening defined in the flange, and a retainer element is inserted into a slot formed on the electromagnetic sensor head such that the sensor cannot be extracted from the opening. The flanges are either annular and have an aperture for receiving a wheel shaft, or they have bushings for receiving a fastener to secure the wheel speed sensor to a vehicle.

BACKGROUND

The present invention relates to a wheel speed sensor, and preferably a wheel speed sensor and monitoring system for a wheeled vehicle.

SUMMARY

In one embodiment, the invention provides a wheel speed sensor including an electromagnetic sensor comprising: an electromagnetic sensor head disposed at a distal end of the electromagnetic sensor, the electromagnetic sensor head comprising a magnet and an integrated circuit, the electromagnetic sensor head configured to sense movement by a tone ring comprising magnetic attractive material, a communication connector disposed at a proximal end of the electromagnetic sensor and in communication with the electromagnetic sensor head; and a sensor interface disposed at the distal end of the electromagnetic sensor. The wheel speed sensor also includes a flange having a flange interface secured to the sensor interface of the electromagnetic sensor.

In one embodiment, the flange of the wheel speed sensor has an annular shape and includes an open bore aperture, the flange comprising a spacer for receiving a wheel shaft of a vehicle through the open bore aperture.

In another embodiment, the sensor interface and the flange interface are configured to provide a snap fitting connection of the electromagnetic sensor to the flange.

In one embodiment of the wheel speed sensor, the electromagnetic sensor head is a substantially box-shaped electromagnetic sensor head, and the sensor interface is defined by a slot extending about at least three sides of the substantially box-shaped electromagnetic sensor head and a separate retainer element. Further, the flange interface comprises a pair of parallel spaced arms projecting outwardly from the flange, the pair of spaced arms include inwardly facing projections at outward distal ends thereof, wherein the electromagnetic sensor is secured to the flange interface by inserting the substantially box-shaped electromagnetic sensor head between the pair of spaced arms of the flange interface and securement of the retainer element within the slot of the substantially box-shaped electromagnetic sensor head.

In one embodiment of the wheel speed sensor wherein the electromagnetic sensor head comprises a substantially box-shaped electromagnetic sensor head, the sensor interface is flexible tabs projecting outwardly from opposing faces of the substantially box-shaped electromagnetic sensor head and the flange interface comprises a pair of parallel spaced arms projecting outwardly from the flange, said parallel spaced arms having opposing facing apertures, wherein the insertion of the substantially box-shaped electromagnetic sensor head between the parallel spaced arms of the flange interface, with the flexible tabs oriented toward the respective parallel spaced arms, locks the flexible tabs in the apertures to secure the electromagnetic sensor to the flange.

In another embodiment of the wheel speed sensor, the electromagnetic sensor head comprises a substantially box-shaped electromagnetic sensor head, the sensor interface comprises a pair of opposing and outwardly facing projections projecting from opposing sides of the substantially box-shaped electromagnetic sensor head, and the flange interface comprises a pair of semi-rigid, parallel spaced arms projecting outwardly from the flange, the semi-rigid, parallel spaced arms having opposing facing apertures, wherein insertion of the substantially box-shaped electromagnetic sensor head between the semi-rigid, parallel spaced arms, with the projections of the sensor head oriented toward the respective semi-rigid, parallel spaced arms, locks the respective projections into the respective opposing facing apertures to secure the electromagnetic sensor to the semi-rigid, parallel spaced arms.

In another embodiment of the wheel speed sensor, the flange comprises at least one bushing for securing the wheel speed sensor to a fixed part of a vehicle and not with the wheel shaft.

In another embodiment, the tone ring is formed by magnetic attractive material, typically ferrite.

In another embodiment of the wheel speed sensor, the flange comprises one of a plurality of flanges having different shapes for mounting at different mounting locations on a vehicle, each of the plurality of flanges having the same flange interface for securing to the sensor interface of the electromagnetic sensor.

In another embodiment of the invention, a wheel speed monitoring system comprises a wheel speed sensor that includes an electromagnetic sensor with a communication connector disposed at a proximal end and with an electromagnetic sensor head including a magnet and an integrated circuit disposed at a distal end, the communication connector in communication with the electromagnetic sensor head, and a sensor interface disposed at the distal end of the electromagnetic sensor. The wheel speed sensor further includes a flange including a flange interface configured for securement to the sensor interface of the electromagnetic sensor. The wheel speed monitoring system further comprises a tone ring formed of magnetically attractive material for securement to a wheel bearing or wheel, the tone ring including an open bore aperture for receiving a wheel shaft, the tone ring further including one of: a plurality of projecting elements projecting outwardly from one nice of the tone ring and disposed in an alternating pattern at least adjacent an outer edge of the one face of the tone ring, and a plurality of apertures disposed in an aperture pattern at least adjacent an outer edge of the one face of the tone ring, wherein rotation of the tone ring relative to the electromagnetic sensor alters the magnetic field density projected onto an integrated circuit. A magnetic-field sensor, such as Hall sensor or Magneto Resistive sensor in the integrated circuit detects variation of the projected magnetic field density and triggers the integrated circuit to provide an electrical output that is proportional to rotational speed of the tone ring relative to the electromagnetic sensor.

One embodiment also includes a wheel bearing having an aperture for receiving a wheel shaft, and the wheel bearing configured to receive the tone ring.

In another embodiment of a wheel speed monitoring system, the flange comprises a cylindrical shaped ring and an outer element extending outwardly about a portion of the outer circumferential surface of the cylindrical shaped ring, the flange including an open bore aperture for receiving a wheel shaft, wherein the flange acts as a spacer along a wheel shaft.

In one embodiment of a wheel speed monitoring system, the electromagnetic sensor head comprises a substantially box-shaped electromagnetic sensor head, and the sensor interface comprising a slot extending about at least three sides of the substantially box-shaped electromagnetic sensor head and a separate retainer element, wherein the flange interface comprises a pair of parallel spaced arms projecting outwardly from the flange, the pair of parallel spaced arms including facing projections at outward distal ends thereof, and wherein the substantially box-shaped electromagnetic sensor head is secured to the flange interface by insertion of the substantially box-shaped electromagnetic sensor head between the pair of parallel spaced arms of the flange interface and securement of the retainer element within the slot.

In another embodiment of the wheel speed monitoring system, the pair of parallel spaced arms projecting outwardly from the flange are monolithic with the flange, and the magnet and the integrated circuit of the electromagnetic sensor head comprise a magnetic-field sensor.

In another embodiment, the electromagnetic sensor head is a substantially box-shaped electromagnetic sensor head and the sensor interface comprises flexible tabs projecting outwardly from opposing faces of the substantially box-shaped electromagnetic sensor head and the flange interface comprises a pair of parallel spaced arms projecting outwardly from the flange, said parallel spaced arms having opposing facing apertures, wherein insertion of the substantially box-shaped electromagnetic sensor head between the parallel spaced arms of the flange, with the flexible tabs oriented toward the respective parallel spaced arms, locks the flexible tabs in the apertures to secure the substantially box-shaped electromagnetic sensor head to the flange.

In another embodiment, the sensor interface for the electromagnetic sensor comprises a pair of opposing and outwardly facing projections from a substantially box-shaped electromagnetic sensor head, and the flange interface comprises a pair of semi-rigid, parallel spaced arms projecting outwardly from the flange, the semi-rigid, parallel spaced arms having opposing facing apertures, and wherein insertion of the substantially box-shaped electromagnetic sensor head between the semi-rigid, parallel spaced arms with the projections of the substantially box-shaped electromagnetic sensor head oriented toward the respective parallel spaced arms, locks the respective projections into the respective opposing facing apertures to secure the substantially box-shaped electromagnetic sensor head to the parallel spaced arms of the flange interface.

In another embodiment of the wheel speed monitoring system, a plurality of projecting elements projecting outwardly from a face of the tone ring and disposed in a pattern, comprises hills and valleys forming ridges extending outwardly toward the outer edge of the tone ring, wherein the electromagnetic sensor head senses the valleys and hills during rotation of the tone ring.

In another embodiment of the wheel speed monitoring system, the flange comprises one of a plurality of flanges having different shapes for different mounting locations on a vehicle, each of the plurality of flanges having the same flange interface for securement with the sensor interface of the electromagnetic sensor.

In another embodiment of the wheel speed monitoring system, the sensor interface and the flange interface are configured to provide a snap fitting connection of the electromagnetic sensor to the flange.

DETAILED DESCRIPTION

FIG. 1shows an unassembled wheel speed sensor50including an electromagnetic sensor52having a communication connector54at a proximal end and an electromagnetic sensor head60at a distal end. In some embodiments, the communication connector54is a cable harness. The electromagnetic sensor52includes an integrated circuit62and a magnet64(shown inFIG. 2) enclosed within the sensor head60. A sensor interface66, represented by the distal end of the sensor head60enables securement of the electromagnetic sensor52to another object. The communication connector54provides a connection from the integrated circuit62to a remote control unit (not shown). In some embodiments, the integrated circuit62and the magnet64of the electromagnetic sensor head60operates as a magnetic-field sensor. The magnet typically is a permanent magnet.

FIG. 1also shows an annular flange70including an annular or cylindrical shaped metallic ring72and an outer element74extending outwardly about a portion of the outer circumferential surface of the cylindrical shaped ring. In some embodiments, the outer element74is overmolded onto the annular metallic ring72. The annular flange70includes a flange interface76. While shown as a depression for receiving the distal end of the electromagnetic sensor head60inFIG. 1, the flange interface76typically is a physical structure as discussed herein below. The flange70includes an open bore aperture78for receiving a wheel shaft, wherein the flange acts as a spacer along a wheel shaft.

FIG. 2shows the wheel speed sensor50provided adjacent a tone ring80. The tone ring80is a magnetically attractive material, and typically a ferrite that comprises any of several magnetic substances that consist essentially of ferric oxide combined with the oxides of one or more other metals (such as manganese, nickel, or zinc). A ferrite has high magnetic permeability and high electrical resistivity. However, a ferrite does not output a magnetic field, and thus does not act as a magnet. A permanent magnet is not contemplated for the tone ring.

FIG. 3shows a tone ring80having an annular shaped ring82and an open bore aperture84for receiving a wheel shaft therethrough.FIG. 4shows the tone ring80having a plurality of projecting elements86projecting outwardly from one face of the tone ring80. In another embodiment, the plurality of projecting elements are disposed in an alternating pattern that comprises hills and valleys forming ridges extending outwardly toward the outer edge of the tone ring. The projecting elements are teeth in some embodiments. In another embodiment, the projecting elements86are replaced by a plurality of apertures (not shown) extending through the tone ring80and providing an aperture pattern at essentially the same locations as the projecting elements86, or at least adjacent an outer edge of the one face of the tone ring. In some embodiments, a plurality of cavities (not shown) provided in the tone ring80act as closed bore apertures.

FIG. 5shows one embodiment of an electromagnetic sensor90that includes an electromagnetic sensor head92having a substantially box-shape. The electromagnetic sensor90includes a sensor interface94in the form of tabs or ears, such as rigid or flexible tabs, projecting outwardly from opposing sides of the substantially box shaped electromagnetic sensor head92. Other shaped projections94are contemplated. Further, the electromagnetic sensor includes a central part96disposed between the electromagnetic sensor head92at the distal end, and the communication connector98. Finally, a slightly raised cylindrical surface99is shown on a side of the electromagnetic sensor head92to indicate the sensing side to be faced with the tone ring80. The center of the raised cylindrical surface99indicates the position of the integrated circuit62embedded in the electromagnetic sensor head92to be aligned with the tone ring80. Three views of the electromagnetic sensor90are provided to show the overall shape thereof.

FIG. 6shows three views of a flange100or spacer for receiving the electromagnetic sensor90ofFIG. 5to form a wheel speed sensor. The flange includes a metal ring102and an outer element104. The flange100further includes a flange interface106defined by a pair of parallel, outwardly projecting arms107facing each other, and a sensor head receiving slot or opening108therebetween. Finally, the arms107each include open bore apertures109in alignment with each other and are configured to receive the electromagnetic sensor head92. The open bore apertures109are configured to receive the tabs94of the electromagnetic sensor head92.

FIG. 7shows three views of the electromagnetic sensor90and the flange100combined to form a wheel speed sensor110. When combined, the electromagnetic sensor head92is disposed in the sensor head receiving slot108and the tabs94projecting from the electromagnetic sensor head92are locked into the respective apertures109of the flange100. At least one of the arms107or tabs94have a certain amount of elasticity, or are flexible to enable forcing of the electromagnetic sensor head92into the slot108. For instance, the arms are semi-rigid in some embodiments. Upon entrance of the tabs94into the apertures109, a snap fit or locking occurs to for the wheel speed sensor110. In some embodiments, the pair of parallel spaced arms107projecting outwardly from the flange100are monolithic with the flange. In other embodiments, the parallel, spaced arms107are attached or secured to the flange100.

FIG. 8shows front and side views of a wheel hub120. The wheel hub120includes an annular front face122, a wheel bearing receiving aperture124and an inner face126. The aperture124has an inner diameter and the inner face126is flat. While not shown, a path through the wheel hub120for a wheel shaft may be provided.

FIG. 9shows front and side views of a wheel bearing130having a central open bore aperture132extending through the bearing. The wheel bearing130is dimensioned to fit within the bearing receiving aperture124of the wheel hub120.

FIG. 10shows part of a fork140, typically for mounting to a motorcycle. The fork140includes an elongated lower fork bar142having an open bore fork aperture144and an upper fork bar146having a greater dimension in one direction than the lower fork bar.

FIG. 11shows the components for a portion of a cycle wheel assembly wherein the wheel speed sensor50is mounted as a part of the assembly. The components shown are the wheel hub120that receives the wheel bearing130and the tone ring80. Further, the wheel speed sensor50is disposed between the tone ring80and the fork140. The components are assembled in the order shown. An axle or wheel shaft extends through aligned apertures in the components and into through the wheel hub120. The apertures are in axial alignment with each other and similar in diameter.FIG. 12shows the components ofFIG. 11assembled, wherein the wheel hub120, the wheel speed sensor50and the fork140visible. The wheel hub120is configured to receive the wheel bearing130and tone ring80. Thus, the tone ring80is integrated adjacent to the wheel bearing130in the wheel hub120.

FIG. 13shows a perspective view of an embodiment of a wheel assembly150similar to the arrangement ofFIG. 12. InFIG. 13, a wheel shaft152. The wheel shaft152extends through a fork154. The structure155supporting the fork154is only for purposes of illustration. The wheel speed sensor156is disposed adjacent the fork154and the wheel hub158. Portions of the tone ring160are visible facing the wheel speed sensor156. As is illustrated inFIG. 13, the above components all receive the wheel shaft152therethrough. The components ofFIG. 12operate as a wheel speed monitoring system that operates as set forth below.

OPERATION

In operation, the tone ring shown inFIG. 13rotates with a wheel (not shown). As shown inFIG. 2, the integrated circuit62is disposed between the magnet64and the tone ring80. The magnet64projects a magnetic field through the integrated circuit62and the tone ring80. The tone ring80is a magnetic attractive material. Thus, the tone ring80affects the magnetic field projected by the magnet64. Rotation of the tone ring80, and specifically movement of the spaced projections86of the tone ring80past the integrated circuit62cause changes in the magnetic field of the magnet64that are detected by the integrated circuit.

In one embodiment, when the tone ring80is in rotary motion, the magnetic flux density projected onto the integrated circuit62varies in a sinusoidal manner, due to the change in displacement between the magnet64and the outer edge of the tone ring80. In one embodiment, the integrated circuit62contains a magnetic-field sensor such as Hall sensor or Magneto Resistive sensor that senses the variation of the magnetic flux density projected by the magnet64. The integrated circuit62sends electrical signal such as current in different amplitudes corresponding to the variation of the magnetic flux density sensed by its magnetic-field sensor to a control unit via the communication connector54. The frequency of change in the current signal between a low value and a greater value determines the wheel speed.

In conclusion, rotation of the tone ring80relative to the wheel speed sensor50alters magnetic flux density projected by the magnet64sensed by the integrated circuit62, and the integrated circuit62sends an electrical signal, typically current in different amplitudes as an output that is proportional to rotational speed of the tone ring80relative to a control unit via the communication connector54.

The above embodiments are all predicated on the flange70having an open bore aperture78for receiving a wheel shaft. Thus, the above embodiments are all directed to a wheel speed sensor that is disposed on the wheel shaft and acts as a spacer for components thereon. In other embodiments set forth below, the flange of the wheel speed sensor is provided with various shapes for mounting on a vehicle so that the sensor head is disposed adjacent to an outer part of the tone ring for sensing the passage thereby.

In some embodiments, the outer edge of the flat tone ring has an extension projecting perpendicular to the plane of the flat tone ring and extending about the entire circumference of the outer edge. Thus, the extension forms a cylindrical shape. Alternating projections from on outer face or apertures are provided in the extension about the entirety of the extension. Thus, rotation of the tone ring is sensed by a wheel speed sensor that is disposed outwardly of the tone ring. Accordingly, various mounting locations are available and various flanges are needed to locate the wheel speed sensor so that the sensor head is aligned properly with the tone ring.

The embodiments disclosed below permit mounting of an electromagnetic sensor to different flanges to enable use with various vehicles. By utilizing one electromagnetic sensor with a large number of flanges, the cost and time to develop, test and tool for a large number of wheel speed sensors for various vehicles is minimized, as only a large number of receiving flanges are required, that are less expensive and complicated than wheel speed sensors designed for specific vehicles.

FIG. 14shows two views of an embodiment of the wheel speed sensor170having the same or similar snap fit arrangement for mounting the electromagnetic sensor172to the flange174having a bushing176. The arrangement enables a quick and easy snap fitting connection between the electromagnetic sensor172and the flange174. In use, the bushing176is mounted to a fixed part of a vehicle so that the sensor head is aligned near a tone ring for measuring wheel speed.FIG. 15is a perspective view of the embodiment shown inFIG. 14. A fastener (not shown) utilizes the bushing176to mount the wheel speed sensor170.

FIG. 16is another embodiment of the wheel speed sensor180. The embodiment ofFIG. 16is similar to the embodiment ofFIGS. 14 and 15, except the bushing186of the flange184is oriented perpendicular and sidewardly from the bushing arrangement shown inFIGS. 14 and 15. Thus, the wheel speed sensor180ofFIG. 16is mounted in a different vehicle or mounting location to provide the sensor head adjacent the tone ring.

FIG. 17is two views of another embodiment of the wheel speed sensor190. The electromagnetic sensor192has the same snap mounting arrangement with the flange194as the embodiments discussed above. The flange194includes a pair of bushings196for mounting the wheel speed sensor190.FIG. 18is a perspective view the wheel speed sensor190.

In other embodiments (not shown) flanges have bushings that are at 45, 75, 135 or other degree angles with respect to a rear or side of the sensor head of the wheel speed sensor.

FIGS. 19 and 20show another embodiment of a wheel speed sensor200. More specifically,FIG. 19shows an unassembled wheel speed sensor that includes an electromagnetic sensor202having a communication connector204at a proximal end an electromagnetic sensor head206at a distal end. The electromagnetic sensor head206is substantially box shaped. The electromagnetic sensor202has a sensor interface defined by a slot208extending about at least three sides of the substantially box-shaped electromagnetic sensor head206. The slot208is defined by a narrow lip209at the tone ring facing end of the electromagnetic sensor head206. The substantially box-shaped electromagnetic sensor head206is defined by an essentially flat face at the tone ring facing end.

FIG. 19also shows a flange210that acts as a spacer when placed on a wheel shaft. The flange has an annular shape and an open bore aperture212for receiving a wheel shaft. The flange also has a flange interface comprising a pair of parallel outwardly projecting arms214having inwardly oriented projections at the distal ends thereof to receive the electromagnetic sensor head206. A retainer element216is provided for securing the electromagnetic sensor202to the flange210.

FIG. 20shows the assembled wheel speed sensor200formed from the components shown inFIG. 19. More specifically, the electromagnetic sensor head206of the electromagnetic sensor202is located between the arms214that have inwardly oriented projections at the distal ends. A lip at the rear of the electromagnetic sensor head206contacts the arms214while the slot208is adjacent the opposing side of the arms214. Then the retainer element216is seated in the slot208to lock the electromagnetic sensor202and the flange210together to form the wheel speed sensor200that is prepared for use with a wheel shaft.

The wheel speed sensor220shown inFIG. 21is essentially identical to the wheel speed sensor200shown inFIG. 20, except the flange has a reduced length and the pair of parallel outwardly projecting arms are not centered on an outer wall of the cylindrical shaped flange.

FIGS. 22 and 23show the wheel speed sensor200ofFIG. 20disposed on a wheel shaft222adjacent a wheel hub224. The perspective view ofFIG. 23shows a tone ring226disposed in or adjacent the wheel hub224that rotates with a wheel hub. The wheel speed sensor200measures wheel speed in a similar manner to the embodiment discussed above.

FIG. 24shows the electromagnetic sensor202and a separate retainer element216ofFIG. 19, along with a plurality of different flanges230,232,234,236. The different flanges have bushings for mounted to a fixed part of a vehicle. The bushings have different orientations with respect the electromagnetic sensor head206of the electromagnetic sensor202. Thus, the flange for a specific vehicle is selected, secured to the electromagnetic sensor202to form a wheel speed sensor with the retainer element216, and mounted to a vehicle adjacent a tone ring via the bushings and a fastener (not shown).

FIG. 26shows a tone ring280having an annular shaped ring282and an open bore aperture284for receiving a wheel shaft therethrough.FIG. 26shows the tone ring280having a plurality of apertures290disposed in an aperture pattern at least adjacent an outer edge of the one face of the tone ring.

Thus, the invention provides, among other things, an easy approach to providing an easy to assemble wheel speed sensor for mounting on any vehicle. The invention enables a vehicle manufacturer to use a common, validated electromagnetic sensor design, with different mounting flanges for different vehicles that have different mounting constraints, thus substantially reduces the time and costs for developing, testing and tooling for different wheel speed sensors, as the cost of developing, and tooling a new flange, which is a mechanical component that is less complicated than the electromagnetic sensor is minimal compared to a complete wheel speed sensor. Various features and advantages of the invention are set forth in the following claims.