CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This utility patent application claims priority benefit from U.S. Provisional Patent Application Serial No. 63/309,817, filed February 14, 2022 and entitled “Pedal Pad Force Sensors”, the entire contents of which is incorporated herein in its entirety.

TECHNICAL FIELD

[0002] The present specification generally relates to pedal assemblies for vehicles and, more specifically, to force sensing pedal assemblies.

BACKGROUND

[0003] Conventional pedal assemblies include a pedal arm that is pivotally coupled to a housing at one end and a pedal pad positioned on an opposite end. In these pedal assemblies, various inductive or Hall Effect type sensors are positioned within the housing to measure the amount of pivot of the pedal arm with respect to the a target. When a force is applied to the pedal pad, the pedal arm pivots and, based on the amount of pivot, generally electric motors control the vehicle accordingly. However, in floor mounted pedal pads, a user may not apply the same pressure or load over the entire pedal pad. As such, load balancing and measuring small amount of travel of the pedal arm are issues.

SUMMARY

In one aspect, a pedal assembly includes a housing having a cavity. The housing includes an upper housing member separated from a lower housing member. A pedal arm is at least partially received in the cavity. The pedal arm is configured to move within the cavity relative to the housing and apply a force to the upper housing member. A pair of fixed magnets are fixedly attached to the upper housing member and to the lower housing member respectively. Both of the fixed magnets are orientated with similar polarity facing in the same direction. A moveable magnetic is positioned between the pair of fixed magnets, the moveable magnet positioned with a polarity that is opposite of the pair of fixed magnets. A magnetic sensor is positioned in the housing. When a load is applied to the pedal arm, the pedal arm applies a force to the upper housing member moving the moveable magnet in the housing wherein the magnetic sensor senses movement of the moveable magnet indicative of the amount of depression of the pedal arm.

[0004] In another aspect, a pedal assembly includes a housing having a cavity. The housing includes an upper housing member separated from a lower housing member. A pedal arm is at least partially received in the cavity. The pedal arm is configured to move within the cavity relative to the housing and apply a force to the upper housing member. A biasing member is positioned between the pedal arm and the upper housing. A pair of fixed magnets are fixedly attached to the upper housing member and to the lower housing member respectively. Both of the fixed magnets are orientated with similar polarity facing in the same direction. A moveable magnetic is positioned between the pair of fixed magnets, the moveable magnet positioned with a polarity that is opposite of the pair of fixed magnets. A magnetic sensor is positioned in the housing. When a load is applied to the pedal arm, the pedal arm applies a force to the upper housing member moving the moveable magnet in the housing wherein the magnetic sensor senses movement of the moveable magnet indicative of the amount of depression of the pedal arm.

[0005] In a further aspect, a pedal assembly includes a housing having a cavity. The housing includes an upper housing member separated from a lower housing member. A pedal arm is at least partially received in the cavity. The pedal arm is configured to move within the cavity relative to the housing and apply a force to the upper housing member. A biasing member is positioned between the pedal arm and the upper housing. A strain gauge sensor is attached to the biasing member. A pair of fixed magnets are fixedly attached to the upper housing member and to the lower housing member respectively. Both of the fixed magnets are orientated with similar polarity facing in the same direction. A moveable magnetic is positioned between the pair of fixed magnets, the moveable magnet positioned with a polarity that is opposite of the pair of fixed magnets. A magnetic sensor is positioned in the housing. When a load is applied to the pedal arm, the pedal arm applies a force to the upper housing member moving the moveable magnet in the housing wherein the magnetic sensor senses movement of the moveable magnet indicative of the amount of depression of the pedal arm and wherein the strain gauge sensor is configured to sense an amount of deflection of the biasing member indicative of the amount of depression of the pedal arm.

[0006] These and additional features provided by the embodiments described herein will be more fully understood in view of the following detailed description, in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

[0008] FIG. 1 depicts a perspective view of a pedal assembly according to one or more embodiments shown and described herein;

[0009] FIG. 2A depicts a sectional view of the pedal assembly of FIG. 1 in an un- applied position according to one or more embodiments shown and described herein;

[0010] FIG. 2B depicts a sectional view of the pedal assembly of FIG. 1 in an applied position according to one or more embodiments shown and described herein;

[0011] FIG. 3 depicts a front view of magnets of the pedal assembly of FIG. 1 with the housing and spring cup removed according to one or more embodiments shown and described herein;

[0012] FIG. 4 depicts a perspective view of top housing according to one or more embodiments shown and described herein;

[0013] FIG. 5 depicts a perspective view of bottom housing according to one or more embodiments shown and described herein;

[0014] FIG. 6 depicts a side view of top housing and pedal arm according to one or more embodiments shown and described herein;

[0015] FIG. 7 depicts a side view of top housing and pedal arm according to one or more embodiments shown and described herein;

[0016] FIG. 8 schematically depicts a block diagram of the circuit board schematic of the pedal assembly of FIG. 1 according to one or more embodiments shown and described herein;

[0017] Fig. 9 schematically depicts a block diagram of a signal processing of one example strain gauge senor of the pedal assembly of FIG. I according to one or more embodiments shown and described herein. DETAILED DESCRIPTION

[0018] Embodiments described herein are directed to a pedal assembly that includes a pedal arm movably positioned within a cavity of a housing. A proximal end of the pedal arm includes a pedal pad. Three magnets are positioned within the cavity. A magnet sensor is positioned in the housing. The magnet sensor is configured to sense an amount of movement of a middle of the three magnets. A biasing member is positioned between the pedal arm and the top housing. A strain gauge sensor is attached to the biasing member. The strain gauge sensor is configured to sense an amount of the deflection of the biasing member. Various embodiments of the pedal assembly are described in detail herein.

[0019] As used herein, the term “communicatively coupled” means that coupled components are capable of exchanging data signals with one another such as, for example, electrical signals via conductive medium or a non-conductive medium, though networks such as via Wi-Fi, Bluetooth, and the like, electromagnetic signals via air, optical signals via optical waveguides, and the like.

[0020] As used herein “minimal travel” or “reduced travel” or “limited travel” may be interchangeability used and refer to a pedal stroke of the pedal arm needed or required to detect the amount of load or force of the load applied to the pedal pad. In minimal travel pedal applications, the total travel of the pedal arm is 30 millimeters or less. As such, sensing the amount of travel of the pedal arm in these minimal travel applications for brake-by-wire applications must be precise due to the limited amount of pedal stroke. Load balancing of the pedal arm is desirable to detect a load applied to any portion of the pedal pad without the need for a direct center contact of the pedal pad. As such, the aspects of the pedal assemblies described herein are directed to minimal travel pedal assemblies with load balancing and strain gauge sensing that is more sensitive to the load applied to the pedal pad and is immune to load offset to sense any movement of the pedal arm regardless of where the load is applied to on the pedal pad.

[0021] As used herein, the term “longitudinal direction” refers to the forward-rearward direction of the pedal assembly (i.e., in the +/- X-direction depicted in FIG. 1). The term “lateral direction” refers to the cross-pedal assembly direction (i.e., in the +/- Y-direction depicted in FIG. 1), and is transverse to the longitudinal direction. The term “vertical direction” or “up” or “above” or “below” refer to the upward-downward direction of the pedal assembly (i.e., in the +/- Z- direction depicted in FIG. 1). [0022] Referring initially to FIGS. 1-7, a pedal assembly 10 is depicted. The pedal assembly 10 includes a housing 12, and a pedal arm assembly 14. The housing 12 includes a lower housing member 16 and an upper housing member 18. The upper housing member 18 includes an opening 20 formed therein allowing passage of a portion of the pedal arm assembly 14.

[0023] Referring to Fig. 4, the upper housing member 18 includes a first circular body 22 having an upper cavity 24 formed therein. The circular body 22 includes the opening 20. Around a rim 26 of the circular body 22 a plurality of holes 28 are formed therein that receive pins 30 of the lower housing 16 as will be described in more detail below.

[0024] Referring to Fig. 5, the lower housing member 16 includes a second circular body 32 having a lower cavity 34 formed therein. The circular body 32 includes a second opening 36 allowing passage of the pedal arm 24. Around a rim 38 of the circular body 32 a plurality of pins 30 are attached thereon to pass through the holes 28 in the upper housing 18 as described above.

[0025] The housing 12 may be formed of steel or other metal. Alternatively, the housing 12 may be formed of a molded plastic. For example, the housing 12 may be formed with various materials such as acrylonitrile butadiene styrene (ABS), polyethylene (PE), polypropylene (PP), polycarbonate (PC), nylon, polycarbonate/acrylonitrile butadiene styrene, polyurethane, polymethyl methacrylate, high density polyethylene, low density polyethylene, polystyrene, PEEK, POM (Acetal/Delrin), polyethylene terephthalate, thermoplastic elastomer, polyetherimide, theremoplastic vulcanizate, polysulfone, combinations thereof, and/or the like. Additionally, additives may be added such as UV absorbers, flame retardants, colorants, glass fibers, plasticizers and/or the like.

[0026] Referring to Figures 2A, 2B, 6 and 7, the pedal arm assembly 14 includes a pedal arm 40 which includes a pedal pad portion 42 that extends along a shank 44. The shank 44 may include threads 46 formed thereon to engage with a stop nut 48. The stop nut 48 may be utilized to define an amount of travel of the shank 44 within the housing 12. The housing 12 may be floor mounted. That is, in some embodiments, the housing 12 may be coupled or mounted to be positioned within or extending from a floor surface of a vehicle. As such, the cavity 50 of the housing 12 accommodates the pedal arm 40 at full depression to allow the pedal pad 42 to fully travel.

[0027] In some embodiments, the pedal pad 42 is generally circular shaped. It should be realized that various shaped pedal pads 42 may be utilized other that those shown in the depicted embodiment. In one aspect, the pedal pad 42 engages a foot of a user and can depress against to brake, accelerate, and/or activate a clutch control.

[0028] Referring to Figures 1, 2 A and 2B, a biasing member 52 is positioned between the upper housing 18 and the pedal arm 40. In the depicted embodiment the biasing member 52 has a conical shape that tapers as it approaches the upper housing 18. The biasing member 52 includes an opening 54 formed therein allowing passage of the shank 44. A strain gauge sensor 68 is provided that is coupled to biasing member 52 and is configured to sense an amount of the deflection of the biasing member 52.

[0029] Referring to Figures 2A, 2B and 3, three magnets 56 are positioned in the cavity 50 defined between the upper and lower housings 18, 16. A pair of fixed magnets 58 are positioned within the upper housing 18 and lower housing 16 respectively. Both of the fixed magnets 58 are fixedly attached to the upper housing 18 and lower housing 16 and both fixed magnets 58 are orientated with similar polarity facing in the same directions. This provides a repelling force to the middle magnet 60 and as a result force linearity is improved. The middle magnet 60 is moveable within the housing 12 between the pair of fixed magnets 58 and is positioned with a polarity that is opposite of the pair of fixed magnets 58. A magnet sensor 62 is positioned in the housing 12 and is configured to determine movement of the moveable magnet 60.

[0030] The magnet sensor 62 detects movement of the moveable magnet. In some embodiments, the magnet sensor 62 includes a printed wiring assembly and a connector housing 64. The printed wiring assembly may include a circuit board (or a printed circuit board), which may include at least one Asic 66.

[0031] While an embodiment above describes the use of a biasing member 52 to transfer a force to the upper housing member 18, it should be realized that other structures may be utilized. For example the pedal arm may be directly coupled to the upper housing to apply a force to the upper housing. In such an application the strain gauge 68 may be removed from the pedal assembly.

[0032] Now referring to FIG. 8, a block diagram of the circuit board schematic of the pedal assembly 10 is schematically depicted. As depicted, a strain gauge sensor 68 is communicatively coupled to the circuit board 70b while the magnetic sensor 62 is communicatively coupled to the circuit board 70a. The circuit board 70b is communicatively coupled to the connector 64b while the circuit board 70a is communicatively coupled to the connector 64a. As such, data communication between the strain gauge sensor 68 and magnetic sensor 62 to the electronic control unit on the vehicle side is established via the connectors 64a, 64b. Further, such an arrangement permits for a redundancy in sensing any load applied to anywhere on the pedal pad 42 and provides a desirable fail-safe should any of the magnetic sensor 62 or strain gauge sensor 68 and/or circuit boards 70a, 70b or components thereof fail.

[0033] In one aspect, the sensors 62, 68 output a digital signal to the connector 70a or 70b for example, indicative of the current amount of travel of the pedal arm 40. As such, the strain gauge sensor 68 and magnetic sensor 62 provide an improvement over conventional systems by providing a precise measurement io any load applied to any portion of the pedal pad 42. Thai is, the user does not have to center contact with the pedal pad 26 and the load may be applied to any portion of the pedal pad 26. Further, the arrangement of the sensors 62, 68 provide a precise sensing in applications where the pedal pad 42 and pedal arm 40 have a minimal travel.

[0034] Further, each of the corresponding sensors 62, 68 provide a redundancy in sensing capabilities. As depicted in FIG. 8, the strain gauge sensor 68 is communicatively coupled io the circuit board 70b while the magnetic sensor 62 is communicatively coupled to the circuit board 70a. Such an arrangement permits for a redundancy in sensing any load applied to anywhere on the pedal pad 42 and provides a desirable fail-safe should any of the sensors and/or circuit boards or components thereof foil.

[0035] Now referring to FIG. 9, an example application specific integrated circuit (asic) or signal processing of the data sensed by the strain gauge sensor 68 of the example pedal assembly 10 is schematically depicted.

[0036] As depicted, the strain gauge sensor 68 may be a full bridge strain gauge such as a piezoresistive sensing element 1305, arranged as a bridge circuit, and communicatively coupled to a programmable-gain amplifier 1310 and to an analog supply voltage as a VDDA 1315 and output as a divided bridge current though a converter 1320 into a multiplexer 1325. The output from the programmable-gain amplifier 1210 is the second input into the multiplexer 1325, which is then transmitted to an analog-to-digital converter 1330 and is transmitted as an digital signal into the digital signal processor 1335, which outputs a digital signal 1340 to the connector 64b, for example, indicative of the current amount of deflection or bend applied to the biasing member 52.

[0037] In operation, when the pedal pad 42 is depressed the pedal arm 42 moves and compresses the biasing member against the upper housing. The amount of force applied to the biasing member and amount of deflection of the biasing member is detected by the strain gauge sensor 68.

[0038] The force is transferred to the upper housing which moves downwardly. The upper housing moves along the pins of the lower housing in a controlled manner. The fixed magnet disposed in the upper housing applies a force to the movable magnetic which also moves downwardly against the biasing force of the fixed magnet in the lower housing to generate a force feedback to a foot on the pedal pad 42. Movement of the moveable magnet is detected by the magnetic sensor as described above. Such an arrangement permits for a redundancy in sensing any load applied to anywhere on the pedal pad 42 and provides a desirable fail-safe should any of the sensors and/or circuit boards or components thereof fail.

[0039] It is noted that the terms "substantially" and "about" may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[0040] While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. It is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the claimed subject matter.