Spring loaded anti-lock braking system sensor

An anti-lock braking system includes a sensor apparatus that includes a sensor body. In a first position, the sensor body is positioned such that a desired gap is maintained between the sensor body and a reference point located on a tone ring, which is rotatably coupled to a corresponding wheel hub. In the first position, a spring-loaded plunger holds the sensor body in place. When the sensor body is moved to a second position, a plunger pin is displaced within the plunger, putting tension on an internal spring. The tension in the spring returns the sensor body to the first position.

BACKGROUND

Antilock braking systems are commonly employed in trailers and other towable vehicles to control tire slip. The antilock braking systems use wheel speed monitors to monitor relative deceleration rates of wheels while braking and respond to indications of slip by temporarily reducing the hydraulic pressure to the brakes. Typically, wheel speed monitors used in antilock braking systems have two primary components: a sensor and a tone ring.

The tone ring is a structure such as a ring or disk that has a number of reference points (e.g., notched teeth) on it. The tone ring rotates with the wheel and the reference points are sensed by the sensor to generate data about the speed of the corresponding wheel. Sensors typically are fixedly attached to the brake flange such that a desired gap is maintained between the sensor and the tone ring. In most implementations, the wheel speed monitor only functions properly when the particular gap is maintained. However, any number of events can cause some object to exert force on the sensor, pushing it out of position. Typically, a mechanic must then reposition the sensor to achieve the necessary gap.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used, in isolation, as an aid in determining the scope of the claimed subject matter. At a high level, embodiments of the invention relate to a spring-loaded antilock braking system (ABS) sensor apparatus. By using embodiments of the spring-loaded ABS sensor apparatus described herein, if the sensor is hit and knocked out of position, the “spring-loaded” feature allows the sensor to move with the item that is making contact with the sensor and then move the sensor back into its functional position without requiring manual adjustment.

A first illustrative embodiment of the present invention relates to an antilock braking system corresponding to a wheel. The illustrative braking system includes a braking assembly, which includes a brake flange mounted to an axle. A wheel hub is rotatably coupled to an outside end of the axle and has a tone ring attached thereto. A sensor is moveably coupled to the brake flange and senses the reference point to generate data about a speed associated with the corresponding wheel.

A second illustrative embodiment of the present invention relates to an antilock braking system sensor apparatus. According to the illustrative embodiment, the apparatus includes a sensor assembly having a sensor body that extends outwardly from a sensor head. A mounting bracket is attached to a brake flange and includes a bolt housing through which the sensor body extends. The illustrative embodiment further includes a plunger that is fixedly attached to the mounting bracket. In embodiments, the plunger includes a spring-biased plunger pin that engages the sensor head to hold the sensor in a first position and is configured to cause the sensor to return to the first position in reaction to the sensor being moved into a second position.

A third illustrative embodiment of the present invention relates to an antilock braking system. The illustrative braking system includes a braking assembly having a brake flange mounted to an axle. A wheel hub is rotatably coupled to an outside end of the axle and a tone ring having a reference point disposed thereon is coupled to the wheel hub such that the tone ring rotates with the wheel hub. According to embodiments, a sensor is moveably coupled to the brake flange using a mounting bracket and a plunger is fixedly attached to the mounting bracket. The plunger includes a spring-biased plunger pin that engages the sensor head to hold the sensor in a first position, and is configured to cause the sensor to return to the first position in reaction to the sensor being moved into a second position.

These and other aspects of the invention will become apparent to one of ordinary skill in the art upon a reading of the following description, drawings, and the claims.

DETAILED DESCRIPTION

The subject matter of embodiments of the invention disclosed herein is described with specificity to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, the inventor has contemplated that the claimed subject matter might also be embodied in other ways, to include different features or combinations of features similar to the ones described in this document, in conjunction with other technologies. Additionally, as the terms are used herein, an “outside” end or surface refers to an end or surface that faces toward the outside (toward the wheel end of the axle) of a vehicle in which embodiments of the invention are implemented, and an “inside” end or surface refers to an end or surface that faces toward the inside (away from the wheel end of the axle) of the vehicle.

Referring to the drawings, and particularly toFIG. 1, there is depicted an illustrative ABS braking assembly1. The braking assembly1includes an axle2and a brake flange3attached to the axle2. According to various embodiments, the brake flange3can be attached to the axle2in any suitable manner such as, for example, by welding, bolting, and the like. In other embodiments, the brake flange can be integral to the axle2. As illustrated inFIG. 1, a wheel hub4is rotatably coupled to the end of the axle2. The wheel hub4provides attachment for a wheel (not illustrated herein for the purposes of brevity and clarity). Additionally, as depicted inFIG. 1, a rotor5and tone ring6, which includes a body7and a number of reference points8, are attached to the wheel hub4.

According to various implementations of the invention, the braking assembly1can include any number of other features such as, for example, a set of calipers, hoses, bearings, and the like. The illustration inFIG. 1and its corresponding description herein is not intended to limit the components or their configuration to the presented examples and is included only for the purpose of describing embodiments of the invention and providing context for that description.

As illustrated inFIG. 1, the ABS braking assembly1also includes an exemplary sensor apparatus10in accordance with various embodiments of the invention. Turning now toFIG. 2, and with continued reference toFIG. 1, an illustrative sensor apparatus10is depicted in accordance with embodiments of the invention. The sensor apparatus10includes a sensor assembly11that is held in place using a mounting assembly12. Implementations of ABS systems in accordance with embodiments of the invention use an antilock braking controller (not shown for the purposes of brevity and clarity) to measure incipient wheel slip. The brake pressure is modulated based on information about wheel speed, which is determined using a sensor assembly that includes a sensor that senses reference points on a tone ring. The tone ring is coupled to the wheel hub so that it rotates with the wheel.

The sensor assembly11can be any type of suitable sensor assembly such as, for example, those known in the art. As illustrated, the sensor assembly11includes a sensor body13that is coupled, at a base end14(shown only inFIG. 2) to a sensor head15. A collar16is disposed around the sensor body13, near the junction of the sensor body13and the sensor head15. In various embodiments, an insulated wire17extends from the sensor head15and includes, at its other end, a communication connection18(seeFIG. 2), which can be plugged into a communication channel (not shown) that includes, for example, an antilock braking controller.

According to some embodiments of the invention, the sensor body13is preferably cylindrical in shape and includes sensing technologies disposed therein. In other embodiments, the sensor body13can be configured according to other shapes. For instance, the sensor body13could be configured such that its cross-section is square, rectangular, triangular, octagonal, or the like. According to embodiments of the invention, the sensor assembly11can utilize any number of various sensing techniques known in the art such as, for example, magnetic reluctance, Hall effect, optics, and the like.

As illustrated, the sensor body13includes an outside surface19that is oriented in proximity to the tone ring6such that sensor technologies within the sensor body13can sense the reference points8on the tone ring6. In embodiments, for example, the sensor body13can include a wire coil/magnet assembly, which generates pulses of electricity as the reference points8of the tone ring6pass in front of it. In other embodiments, the sensor body13can include a laser, other optical technologies, other types of sensing technologies, and the like. The antilock braking controller uses the electric pulses to determine wheel speeds and rates of acceleration/deceleration.

As indicated above, the tone ring6includes the body7and the number of reference points8. The tone ring body7can be a disc, ring, or any other suitable structure upon which one or more reference points8can be disposed. According to various embodiments, the reference points8can be anything that can be observed by a sensor. In some embodiments, for example, the tone ring6is a ring with notched teeth that serve as the reference points8. In other embodiments, the tone ring6can include raised teeth that serve as the reference points8. One commonly used tone ring6has 100 evenly spaced teeth, but the number of teeth can vary depending on the implementation design. In embodiments, the tone ring6can be a separate entity from the wheel hub4and, in other embodiments, the tone ring6can be integral to the wheel hub4. In still further embodiments, the tone ring6and the rotor5can be the same structure.

With more particular reference toFIG. 2, the mounting assembly12includes a mounting bracket20. In embodiments of the invention, the mounting bracket20is a solid, U-shaped bracket and includes a first arm member21, a second arm member22that is substantially parallel to the first arm member21, and a connecting member23. That is, the first arm member21is coupled, at a first end24, to a first end25of the connecting member23and extends substantially perpendicularly away from the connecting member23in a first direction. The second arm member22is connected, at a first end26, to the second end27of the connecting member23and extends substantially perpendicularly away from the connecting member23, also in the first direction. In embodiments, as illustrated, a first opening28is disposed in first arm member21, and a second opening29is disposed in the second arm member22. In embodiments, the mounting bracket20can be made from any suitable material such as, for example, steel.

As shown inFIG. 1, the mounting bracket20can be oriented such that an outside surface30of the second arm member22is disposed against an inside surface31of the brake flange3such that the second opening29is aligned with an opening32in the brake flange3. As illustrated, the mounting assembly12includes a bolt housing33. In embodiments, the bolt housing33includes a hollow threaded body34having an opening34atherethrough. In embodiments, a housing flange35is attached to a first end36of the bolt housing33. In embodiments, the housing flange35can be integral to the threaded body34and, in other embodiments, the housing flange35can include a nut that is screwed onto the first end36of the threaded body34.

The bolt housing33is positioned such that the threaded body34passes through the second opening29in the mounting bracket20and the opening32in the brake flange3. For example, in embodiments, the bolt housing33can be pushed through the two openings29and32, in a direction away from the first arm member21of the mounting bracket20(e.g., toward the outside of the vehicle) until its further movement is prohibited by the engagement of the housing flange35with an inside surface39of the second arm member22(seeFIG. 1). The bolt housing33is held in place by a nut40. Threads41aon the inside of the nut40engage threads41bon the threaded body34so that the nut40can be screwed onto the threaded body34so that an inside surface42of the nut40engages the outside surface43of the brake flange3such that an outside surface44of the nut40is oriented away from the brake flange3. The engagement of the nut40with the brake flange pulls the housing flange35against the inside surface39of the second arm member22, holding the mounting bracket20in place on the brake flange3and further holding the bolt housing33in place, disposed through the openings29and32on the second arm member22of the mounting bracket20and the brake flange3, respectively.

With further reference to the drawings, and, in particular,FIG. 2, the sensor body13is moveably disposed within the bolt housing33such that the outside surface19of the sensor body13extends from a second end45of the bolt housing33toward the tone ring6. It will be appreciated by individuals having skill in the relevant arts that the sensor body13is positioned within the bolt housing33such that a predetermined gap46(seeFIG. 1) is achieved between the outside surface19of the sensor body13and the reference points8on the tone ring6. Because the specific dimensions of various features employed in ABS braking systems can vary, any number of spacing shims47can be utilized to achieve the desired gap46.

As depicted, for example, inFIG. 2, the spacing shims47, which can be crafted of any suitable material known in the art, are configured such that they can be disposed around the sensor body13. For example, in embodiments in which the sensor body13is cylindrical, the shims47are circular with an internal diameter slightly larger than the external diameter of the sensor body13. When the sensor body13is placed into the bolt housing33, an outside surface48of an outermost shim47engages the first, or inside, end36of the bolt housing33and an inside surface49of an innermost shim47engages an outside surface50of the collar16. The desired gap46can be achieved by inserting an appropriate number of spacing shims47, which can, according to various embodiments, be configured of varying thicknesses depending upon the details of the implementation. It should be understood that, in some embodiments, the length of the bolt housing33, itself, might be appropriate for achieving a desired gap46in which case no spacing shims47may be needed. It should also be understood that, in some embodiments, the outermost shim47and the innermost shim47might be the same shim47(i.e., when only one spacing shim47is employed).

With reference toFIGS. 2-4, the sensor apparatus10also is shown to include a spring-loaded plunger51. As illustrated inFIGS. 3 and 4, the plunger51includes a threaded body52, a plunger pin53, a pin casting54, a pair of springs55aand55b, and a retaining ring56. The threaded body52is configured to be able to be inserted into the first opening28, which is disposed in the first arm member21of the mounting bracket20. The threaded body52includes threads57onto which a first nut58and a second nut59can be screwed. As shown, for example, inFIG. 2, the first nut58is screwed onto the threaded body52such that an outside surface60of the first nut58engages an inside surface61of the first arm member21of the mounting bracket20. The second nut59is screwed onto the threaded body52such that an inside surface62of the second nut59engages the outside surface63of the first arm member21. When tightened, the nuts58and59hold the plunger51in place.

With continued reference toFIGS. 3 and 4, the plunger pin53includes a plunger pin body53ahaving a cavity53bwith threaded walls disposed therein. An adjustment assembly65is disposed at an outside end64of the plunger pin body53a. As shown inFIGS. 3 and 4, the adjustment assembly65includes a moveable screw66having a threaded shaft67and a flanged head68. The threads on the screw66engage threads on the inside of a nut69and threads on the inside of the plunger pin body53a, such that the nut69engages an outside end71of the plunger pin body53a. In some embodiments, the screw66is screwed directly into the plunger pin body53a, without the inclusion of the nut69. According to various embodiments of the invention, the screw66can be screwed in and out of the plunger pin body53asuch that an outside surface73of the screw66can be positioned as desired. The adjustment assembly65allows for fine-tuning the position of the plunger pin53with respect to the sensor head15, as shown inFIG. 1.

As is further illustrated inFIG. 1and indicated above, the plunger51includes a plunger pin53that is partially disposed within the threaded body52. In its normal position, the spring55ais compressed and the spring55bis extended, keeping the plunger pin53in a first position. In this first position, when the plunger51is coupled to the mounting bracket20in an implementation of the invention, the outside end73of the plunger pin53engages an inside surface74of the sensor head15, holding the sensor assembly11in place. In various embodiments, the plunger51can be any type of suitable plunger that includes an internal elastic mechanism such as, for example, a spring that allows return of the sensor head15to the first position subsequent to displacement from the first position.

During installation of an illustrative sensor apparatus10in accordance with various embodiments of the invention, the mounting bracket20is placed against a brake flange3such that a second opening29in a second arm member22of the mounting bracket20is aligned with an opening32in the brake flange3. In embodiments, a flanged bolt housing33is passed through the two openings,29and32until an inside surface76of the housing flange35engages the inside surface39of the second arm member22of the mounting bracket20. The nut40is screwed onto the other end45of the bolt housing33until the inside surface42of the nut40engages the outside surface43of the brake flange3, thereby securing the mounting bracket20to the brake flange3. The sensor assembly11is mounted on the mounting bracket20by way of inserting the sensor body13through the inside, open end36of the bolt housing33and pushing the sensor body13through the bolt housing33such that the outside surface19of the sensor body13extends outwardly from the outside end45of the bolt housing33.

In this manner, the sensor body13can be placed in proximity to the tone ring6such that the outside surface19of the sensor body13is disposed near the tone ring6, there being a predetermined gap46between the outside surface19of the sensor body13and the reference point8on the tone ring6. In embodiments, this gap46can be achieved by sliding one or more spacing shims47onto the sensor body13before inserting the sensor body13through the bolt housing33. When pushed into place, the shims47engage a collar16on the sensor head15and the housing flange35on the inside end36of the bolt housing33. The spacing shims47prevent the sensor body13from moving any farther through the bolt housing33toward the outside, thereby defining the gap46between the sensing surface19of the sensor body13and the reference point8on the tone ring6.

According to various embodiments of the invention, and as shown inFIGS. 1 and 2, the plunger51is inserted through the first opening28defined in the first arm member21of the mounting bracket20. In embodiments, the plunger51includes the threaded body52that is configured to engage the inside walls of the first opening28. In other embodiments, the plunger51is configured such that the cross-sectional area of the plunger is slightly less than the cross-sectional area of the opening28, thereby allowing the plunger51to be inserted into the opening28. An outside surface73of the plunger pin53that extends from the plunger body52is moved toward an inside surface74of the sensor head15until the outside surface73of the plunger pin53(which, in embodiments, can be an outside surface73of the moveable screw66of the adjustment assembly65) engages the inside surface74of the sensor head15. The plunger51is fastened into this position, thereby holding the sensor body13in place.

In embodiments, as illustrated inFIGS. 1,2, and5, the plunger51is fastened into position by screwing the first nut58onto an inside end78of the threaded body52of the plunger51and the second nut59onto an outside end80of the plunger body52. The nuts58and59are tightened such that an outside surface60of the first nut58engages an inside surface61of the first arm member21of the mounting bracket20and an inside surface62of the second nut59engages an outside surface63of the first arm member21of the mounting bracket20, holding the plunger body52in place. This configuration (which is characterized, at least in part, by the existence of the gap46between the reference point8and the outside surface19of the sensor body13) is referred to herein as the first position, as shown, for example, inFIG. 6A.

In operation, as will be appreciated by individuals having skill in the relevant arts, the sensor body13can be knocked out of the first position by any number of various events. For example, in the case of trailers/towable vehicles, a sharp turn can cause the wheel hub to tilt, as illustrated, for example, inFIG. 6B, such that the tone ring6(and/or the reference points8disposed thereon) makes contact with the outside surface19of the sensor body13, thereby pushing the sensor body13out of the first position. Of course, any number of other events such as, for example, the introduction of road debris, an encounter with a curb or other obstacle, and the like, may cause the sensor20to move from the first position.

Turning now toFIGS. 6A and 6B, an illustrative sensor assembly is depicted in a first position82and a second position84, respectively, in accordance with embodiments of the invention. The position to which the sensor body13is moved, regardless of where that is, is referred to herein as the second position84. As illustrated inFIG. 6A, in the first position82, a desired gap46is maintained between outside surface19of the sensor body13and a reference point8on the tone ring6. Additionally, in the first position82, the outside surface73of the plunger pin53engages the inside surface74of the sensor head15, thereby holding the sensor assembly11in place. According to various embodiments of the invention, the spring55ais in a compressed, normal, configuration in the first position82and the spring55bis in an extended, normal, configuration in the first position82. In other embodiments, the plunger51can be configured such that the normal position of the spring55ais an extended configuration and the normal position of the spring55bis a compressed configuration (whereby the spring55awill be compressed, rather than stretched, in the second position84and the spring55bwill be extended, rather than compressed, in the second position84).

In embodiments of the invention, in the second position84shown inFIG. 6B, the sensor head15pushes against the plunger pin53, displacing the plunger pin53within the plunger body52. This displacement extends the spring55abeyond its normal, compressed, position and compresses the spring55bbeyond its normal, extended, position. The tension of the springs55aand55burge the springs55aand55bback to their normal positions, thereby applying a thrusting force on the plunger pin53. This outwardly thrusting force on the plunger pin53causes the application of an outwardly force on the sensor head15, which attempts to push the sensor body13back into the first position82. Because the sensor body13generally is configured such that normal operation depends upon the existence of the gap46(and, therefore, a particular position of the sensor body13), embodiments of the invention allow for automatic recovery of the sensor body13position after events that push the sensor out of the first position82.