Variable resistance pedal assembly

Abstract

A variable resistance pedal assembly (100) for use in a vehicle includes a pedal (104) pivotally moveable between a plurality of operational states including a first operational state, a second operational state and an infinite number of intermediate operational states between the first and second operational states. The assembly also includes a hydraulic damper (130) to dynamically control an effort of the pedal in one or more of the operational states and during one or more movements between the operational states and a pedal position sensor (190) coupled to the pedal. The assembly also includes a controller (200) electrically coupled to each of a fluid valve (170), a fluid temperature sensor (183), an optional fluid pressure sensor (180), and a pedal position sensor with the controller pre-programmed to choose a valve position for the fluid valve based upon at least a measured pedal position that correlates to one of the operational states and a measured temperature.

Description

VARIABLE RESISTANCE PEDAL ASSEMBLYCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The subject disclosure claims priority from U.S. Provisional Patent No. 63 / 590,667, filed on October 16, 2023, the disclosure of which is incorporated by reference in its entirety herein.FIELD OF THE DISCLOSURE

[0002] This disclosure generally relates to pedal assemblies for vehicles and more particularly to a variable resistance pedal suitable for use in a vehicle.BACKGROUND OF THE DISCLOSURE

[0003] Variable resistance pedal assemblies for vehicles are known and are used to dynamically change the pedal effort used on a vehicle for braking or for acceleration. Such assemblies generally use mechanical means such as springs to adjust the force required to pivot the pedal between a resting state and a depressed state. The subject disclosure provides an electro- hydraulic method for improving these types of assemblies and their use in vehicles.SUMMARY OF THE DISCLOSURE

[0004] The subject disclosure provides a variable resistance pedal assembly for use in a vehicle.

[0005] The pedal assembly includes a pedal moveable between a plurality of operational states. These operational states include a first operational state, a second operational state and an infinite number of intermediate operational states between the first operational state and the second operational state. The assembly also includes a hydraulic damper to dynamically control an effort of the pedal in one or more of the operational states and during one or more movements between the operational states. The hydraulic damper includes a fluid housing defining a fluid system through which a fluid moves as the pedal moves between the plurality of operational states, thefluid system including a first chamber fluidically coupled to a second chamber. The hydraulic damper also includes a temperature sensor having a sensor housing defining a fluid inlet fluidically coupled to the fluid system, and a fluid valve moveable between an opened valved position and a closed valved position and a plurality of intermediate valve positions between the open valve position and the closed valve position, the fluid valve fluidically coupled to the fluid system. The assembly also includes a push rod defining a length between a first end and a second end with the first end coupled to the pedal and the second end disposed within the second chamber of the fluid system and a pedal position sensor coupled to the pedal that is configured to measure a relative position of the pedal in each of the plurality of operational states. The assembly also includes a controller electrically coupled to each of the fluid valve, the temperature sensor, and the pedal position sensor with the controller pre-programmed with one or more programs to choose a valve position for the fluid valve based upon at least a measured pedal position from the pedal position sensor that correlates to an operational state from the plurality of operational states. The chosen valve positions include the opened valved position, the closed valved position or one of the plurality of intermediate valve positions to dynamically control the effort of the pedal by controlling the flow of fluid through the fluid system. In certain embodiments, the assembly also includes a fluid pressure sensor fluidically coupled to the fluid system. In certain embodiments, the controller also chooses the valve position based upon one or both of a measured fluid pressure and temperature from the fluid pressure sensor and fluid temperature sensor, respectively.

[0006] The subject disclosure also provides an associated method of use of the variable resistance pedal assembly as described above in a vehicle to control the vehicle which includes the steps of: applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states, measuring the pedal position of the pedal using the pedal position sensor at the second one of the plurality of operational states; measuring the temperature of the fluid using the temperature sensor at the second one of the plurality of operational states; and using the controller to adjust a valve position of the fluid valve to the chosen valve position at the second one of the plurality of operational states based at least on the measuredpedal position and the measured temperature of the fluid during said step of applying force to pivot the pedal.

[0007] In further embodiments, the method also includes measuring the pressure of the fluid using the fluid pressure sensor at the second one of the plurality of operational states, wherein the controller adjusts a valve position of the fluid valve to the chosen valve position at the second one of the plurality of operational states also based on the measured fluid pressure.

[0008] The variable resistance pedal assembly therefore provides communication between the pedal and the machine operator / user by dynamically altering the pedal resistance in real-time in response to inputs from the vehicle controller and sensors. In the absence of an external overriding input to the controller, the pedal assembly follows a selected one of the programs throughout the pedal's range of travel between the first and second operational states. The variable resistance pedal assembly is intended to be used for an accelerator, a brake, a clutch, or to otherwise implement control in the off-highway, agriculture, and construction equipment markets. It is to be appreciated, that the pedal assembly is suitable for any type of vehicle. The variable resistance pedal assembly is a fast acting, small, self-contained assembly that can provide an infinite number of possible pedal control variations for the machine operator / user.BRIEF DESCRIPTION OF THE FIGURES

[0009] Advantages of the subject application will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

[0010] FIG. 1 is a perspective view of a variable resistance pedal assembly according to one exemplary embodiment for use on a vehicle.

[0011] FIG. 2. is an exploded view of FIG. 1.

[0012] FIG. 3 is a partially exploded view of FIG. 1 rotated 90 degrees.

[0013] FIG. 4 is a partial section view of the variable resistance pedal assembly of FIG. 1 with a pedal of the variable resistance pedal assembly positioned in the first operational state prior to the user applying force to pivot the pedal from the first operational state towards the second operational state and a fluid valve in a fully opened position.

[0014] FIG. 5A is a section view of the variable resistance pedal assembly of FIG. 4 with a pedal of the variable resistance pedal assembly positioned adjacent to the first operational state immediately after the user begins applying force to pivot the pedal towards the second operational state and with the fluid valve remaining in the fully opened position.

[0015] FIG. 5B is a section view of the variable resistance pedal assembly of FIG. 4 with a user / operator applying force to pivot a pedal of the variable resistance pedal assembly towards a second operational state and with the pedal in an intermediate operational state between the first operational state and the second operational state and with the fluid valve remaining in the fully opened position.

[0016] FIG. 5C is a section view of the variable resistance pedal assembly of FIG. 4 with a user / operator applying force to pivot a pedal of the variable resistance pedal assembly towards a second operational state and with the pedal in the second operational state and with the fluid valve remaining in the fully opened position.

[0017] FIG. 6 is another section view of the variable resistance pedal assembly of FIG. 4 with a user / operator removing force to pivot the pedal of the variable resistance pedal assembly towards a first operational state and with the pedal in the same intermediate operational state as the pedal in FIG. 5B and with the fluid valve remaining in the fully opened position.

[0018] FIG. 7 is a top section view of the variable resistance pedal assembly.

[0019] FIG. 8 is side section view of the variable resistance pedal assembly.

[0020] FIG. 9 is a perspective view of the fluid valve.

[0021] FIGS. 10A, 10B, and 10C are close-up section views of the fluid valve in the fully opened position, a partially opened position, and a fully closed position, respectively.

[0022] FIG. 11 is a graph comparing hydraulic pressure for varying degrees of pedal travel for three preprogrammed pedal force curves for use in the variable resistance pedal assembly according to an embodiment of the subject disclosure.

[0023] FIG. 12 is a graph comparing pedal force for varying degrees of pedal travel for three preprogrammed pedal force curves for use in the variable resistance pedal assembly according to an embodiment of the subject disclosure.DETAILED DESCRIPTION OF THE DISCLOSURE

[0024] Referring to the FIGS. 1-9 and 10A-10C, wherein like numerals indicate like or corresponding components throughout the several views, a variable resistance pedal assembly 100configured for use by a user / operator in a vehicle is shown. In particular, the variable resistance pedal assembly 100 is intended to be used for accelerator, brake, clutch, or to otherwise implement control in the off-highway, agriculture, and construction equipment markets. It is to be appreciated that the pedal assembly of the subject invention could be implemented into any suitable vehicle.

[0025] The pedal assembly 100 includes a pedal housing 102 with a base portion 103 of the pedal housing 102 configured to be mounted on a vehicle. In the embodiment illustrated, a pedal 104 is pivotally coupled to the pedal housing 102. Alternatively, the pedal 104 could be mounted directly to the vehicle. The pedal 104 is mounted or otherwise coupled to a shaft 108, here shown as a trunnion shaft 108, and is configured to pivot relative to the pedal housing 102 with the shaft 108 rotating about an axis A defined by the shaft 108 relative to the pedal housing 102. In other words, the pedal 104 and the shaft 108 are configured for concurrent rotation. The pedal 104 is moveable between (and including) a plurality of operational states including a first operational state (corresponding to a non-braking or non-accelerating operational state, for example, also referred to as a resting position or state), a second operational state (corresponding to a maximum braking or a maximum accelerating operational state, for example, corresponding to a maximum pivoted position or state) and an infinite number of intermediate operational states between the first and second operational state. In a preferred embodiment, the pedal 104 is a treadle pedal having a bottom side 105 (corresponding to a bottom surface of the pedal 104) and an opposing top side 106 (corresponding to top surface of the pedal 104) with the top side 106 configured to receive input from a machine operator / user’s foot to move the pedal 104 to one of the operational states. For ease of description, the term “treadle pedal” and “pedal” may be used interchangeably hereinafter and are identified by reference numeral 104. Similarly, the term “trunnion shaft” and “shaft” may be used interchangeably hereinafter and are identified by reference numeral 108.

[0026] In certain embodiments, the pedal assembly 100 also includes a haptic motor 112 coupled to the bottom side 105 of the pedal 104. The haptic motor 112 is configured to add tactile feedback to the user through the use of vibrations when the user applies force to the top side 106 of the pedal 104 to pivot the pedal 104 about the axis defined by the shaft 108.

[0027] The pedal assembly 100 includes a u-shaped bracket 107 which is mounted to, or integrally formed with, the base portion 103 of the pedal housing 102. The u-shaped bracket 107 includes a pair of upright flanges 109, with each of the flanges 109 defining an opening 111 with the openings 111 aligned along the axis A. The bottom side 105 of the pedal 104 also includes apair of spaced apart projections 113 each defining an opening 115, with the spacing between the projections 113 being less than the spacing between the upright flanges 109 of the bracket 107. In an alternative embodiment (not shown), the projections 113 could be positioned outside of the flanges 109, and thus in this embodiment the spacing between the projections 113 is greater than the spacing between the upright flanges 109 of the bracket 107.

[0028] The assembly 100 also includes a spring, here shown as a torsion spring 120, which includes a coiled portion 122 extending between a first end 124 and a second end 126, with the coiled portion 122 disposed around the shaft 108. An extended loop 125 may be contained within the coiled portion 122. The torsion spring 120 biases the pedal 104 towards the first operational state.

[0029] In the assembled state, the pedal 104 is positioned such that projections 113 are positioned between the pair of upright flanges 109 (or the flanges 109 are positioned between the projections in the alternative embodiment) with the openings 111 of the flanges 109 aligned with the openings 115 of the projections 113 along the axis A. The trunnion shaft 108 extends through each of the aligned openings 111 and 115 of the pedal 104 and bracket 107 such that the pedal 104 is pivotally coupled to the bracket 107 about axis A. In addition, the coiled portion 122 of the spring 120 is wrapped around the trunnion shaft 108 with the extended loop 125 of the torsion spring 120 retained within or otherwise positioned adjacent base portion 103 of the pedal housing 102 and with the first end 124 and the second end 126 retained by or otherwise affixed adjacent to the bottom side 105 of the pedal 104 (see FIG. 1).

[0030] The assembly 100 also includes a hydraulic damper 130 which coordinates an electro- hydraulic method to dynamically control an effort of the pedal 104 in one or more of the operational states and during one or more movements between the operational states.

[0031] The hydraulic damper 130 includes a fluid housing 142 which is positioned onto or integrally formed with the base portion 103. The fluid housing 142 defines a fluid system 140 through which a fluid, such as a hydraulic fluid 146, moves as said pedal 104 moves between the plurality of operational states. The fluid housing 142 can also include an angled inlet opening 148 (see Figure 3).

[0032] The fluid system 140 may be further defined as a fluid chamber 144 that contains the hydraulic fluid 146. The fluid system 140, or fluid chamber 144, is further defined to include a plurality of chambers through which the hydraulic fluid 146 flows as the pedal 104 moves betweenits operational states. In particular, the fluid system 140, or fluid chamber 144, includes a first chamber 150, or reservoir chamber 150, that is fluidically coupled to a second chamber 152, or piston chamber 152, through a plurality of fluid lines.

[0033] The fluid system 140 also includes a plurality of fluid lines fluidically coupling the first chamber 150 and second chamber 152. In the illustrated embodiment, as best shown in FIGS. 4, 5A-C, 6 and 7, the fluid system 140, or fluid chamber 144, includes the first chamber 150 that is fluidically coupled to the second chamber 152 through one or more first fluid lines 154 (shown here as a pair of first fluid lines 154A and 154B). In addition, the fluid chamber 144 also includes a second fluid line 156 that separately fluidically couples the reservoir chamber 150 and the piston chamber 152. The second fluid line 156 extends between a first end 157, adjacent the piston chamber 152, and a second end 159, adjacent to a fluid valve 170 and a bypass line 161 which are each fluidically coupled to the reservoir chamber 150.

[0034] The hydraulic damper 130 also includes a push rod 162 coupled at one end to the bottom side 105 of the pedal 104. The opposing end of the push rod 162 includes a piston 164. The push rod 162 is positioned such that a portion of its length between the pedal 104 and the piston 164 is contained within the piston chamber 152. The piston 164 is sealingly contained within the piston chamber 152 by an upper seal 166 and lower seal 168.

[0035] Preferably, the push rod 162 is a component extending in length between a first end coupled to the bottom side 105 of the pedal 104 and a second opposing end disposed within the second chamber. The second end of the push rod 162 preferably includes the piston 164. As shown, the push rod 162 may include multiple components extending along its length that are secured or otherwise coupled together.

[0036] The hydraulic damper 130 also includes a coil spring 163 engaging with the push rod 162, and in particular engaging with the piston 164 within the piston chamber 152. More in particular, and as illustrated in the FIGS. 4, 5A-C, and 6, the coil spring 163 wrapped around the piston 164 and positioned under tension between a ledge 165 of the piston 164 and a lower end of the piston chamber 152 adjacent to the opening to the second fluid line 156. The ledge 165 is positioned adjacent the lower seal 168 and in a direction towards the opening to the second fluid line 156 relative to the lower seal 168. The coil spring 163 engages the push rod 162, and in certain embodiments the piston 164, to bias the pedal 104 towards the first operational state.

[0037] The hydraulic damper 130 also includes a fluid valve 170, here shown as a proportional solenoid valve 170, and a fluid pressure sensor 180 that are each fluidically coupled within a portion of the fluid system 140. The term “fluid valve 170” is not limited to proportional solenoid valve 170 as described below but can include other types of valves that are controllable to open and close to allow the flow of hydraulic fluid 146 through the fluid system 140. For ease of description, the term fluid valve 170 is utilized below and includes, as one embodiment, the proportional solenoid valve 170.

[0038] The fluid valve 170 includes a valve housing 171, shown schematically in the FIGS, as a solenoid valve housing 171, that defines a fluid inlet line 172 and a fluid outlet line 174, with the inlet line 172 and outlet line 174 separated by a two-way valve 176. The fluid inlet line 172 is fluidically coupled to the second end 159 of the second fluid line 156, and the outlet end of the fluid outlet line 174 is fluidically coupled to the reservoir chamber 150.

[0039] In the embodiments shown, the fluid outlet line 174 includes a plurality of fluid outlet lines 174 (shown as four fluid outlet lines 174A-174D) positioned radially outward and around the fluid inlet line 172. The plurality of fluid outlet lines 174 extend away from the two-way valve 176 with the opposing ends fluidically coupled to a ring shaped channel 175 that is defined by a portion of the valve housing 171. The outer surface 177 of the ring-shaped channel 175 is sealingly engaged to a chamber housing 151 of the first chamber 150 and surrounds an opening 178 defined within the chamber housing 151. The chamber housing 151 is a component of the fluid housing 142. The opening 178 in the chamber housing 151 thus fluidically couples the ring-shaped channel 175 of the fluid valve 170 to the first chamber 150. As shown, the opening 178 has a kidneyshaped configuration, but could be of any suitable shape.

[0040] When the two-way valve 176 is opened (i.e., in an opened valve position, such as shown in FIG. 10A), or partially opened (as shown in one partially opened valve position in FIG. 10B) hydraulic fluid 146 is free to flow through the two-way valve 176 between the fluid inlet line 172 and the fluid outlet line 174, as shown by dashed flow arrow 225 and also corresponding to fluid flow 300. Conversely, when the two-way valve 176 is closed (i.e., in a closed valve position, as shown in FIG. 10C). the fluid 146 remains on either side of the two-way valve 176, as best shown by dashed flow arrows 250A and 250B (with the flow arrows of fluid flow 250A and 250B terminated with X’s to represent no fluid flows through the valve 176 (i.e., either fluid flow 300 or reverse fluid flow 320).

[0041] The relative amount of hydraulic fluid 146 flowing through the valve 176 between the fluid inlet line 172, and the fluid outlet line 174 per unit time is proportional to the degree in which the two-way valve 176 is opened, with an increasing relative flow per unit time occurring as the two-way valve 176 is incrementally opened from the closed valve position towards the opened valve position, with the maximum hydraulic fluid flow rate per unit time in either direction through the valve 176 occurring in the opened valve position.

[0042] As noted above, the second end 159 of the second fluid line 156 is also connected to the bypass line 161. The bypass line 161 bypasses the fluid valve 170 to separately allow fluid flow between the reservoir chamber 150 and the piston chamber 152. A mechanical pressure relief valve 158 is disposed within the bypass line 161 or is otherwise coupled to the fluid housing 142 and disposed within the bypass line 161 and is configured to open to allow hydraulic fluid 146 flow from the piston chamber 152 to the reservoir chamber 150 through the bypass line 161 under certain conditions and particularly when the two-way valve 176 is closed but also under extreme conditions even when the two-way valve 176 is in one of the partially opened positions or the fully opened position. In particular, the mechanical pressure relief valve 158 is configured to open when the hydraulic fluid 146 pressure on the second fluid line 156 side of the valve 158 in the bypass line 161 exceeds a certain hydraulic fluid pressure threshold value and closes once the hydraulic fluid 146 pressure on second fluid line 156 side of the pressure relief valve 158 is at or below this threshold value (this possible fluid flow is shown as a dashed line 311 in each of FIGS. 5A-C and 6 - with the dashed line 311 terminated at both ends with an X to symbolize that in the configuration of 5A-C and 6 no fluid flow is allowed because the valve 158 is illustrated in the closed position).

[0043] Further, the hydraulic damper 130 also includes the fluid pressure sensor 180 having a sensor housing 181 that defines a fluid inlet opening 184 that is fluidically coupled to the first end 157 of the second fluid line 156. The fluid inlet opening 184 includes a sensor (z. e. , a fluid pressure sensor 180) which measures the pressure of the hydraulic fluid 146 in the second fluid line 156. The fluid pressure sensor 180 (shown generically in the FIGS.) is coupled to the fluid pressure system 140 and measures the pressure of the hydraulic fluid 146 in the fluid system 140.

[0044] In certain embodiments, the hydraulic damper 130 also includes a temperature sensor 183 as a separate component to or, in certain embodiments and as illustrated in the FIGS., as part of combined componentry with the fluid pressure sensor 180 (z'.e. , a fluid and temperature sensor182, also referred to as a sensor assembly 182, that includes both the fluid pressure sensor 180 and the temperature sensor 183). The temperature sensor 183 is also fluidically coupled to the fluid system 140 and functions to measure the temperature of the hydraulic fluid 146 in the fluid system 140.

[0045] Still further, the hydraulic damper 130 also includes a pedal position sensor 190. In the illustrated embodiments, the pedal position sensor 190 is coupled to the base portion 103 adjacent to the pedal 104. The pedal position sensor 190 measures the relative position of the pedal 104 in each of its operational states, including when the user is applying force onto the top side 106 of the pedal 104 (shown by force arrows Fl in FIGS. 5A-5C) to pivot the pedal 140 away from the first operational state or when the user is not applying force onto the top side 106 of the pedal 104 and the pedal 104 is pivoting or is pivoted back towards the first operational state due to the force applied by the springs 120, 163 directly or indirectly through the push rod 162 (shown by force arrow F2 in FIG. 6) to the bottom side 105 of the pedal 104. In particular, the shaft 108 may include a magnet 119 that the pedal position sensor 190 senses via changes in the magnetic field as the shaft 108 rotates in conjunction with the pivoting movement of the pedal about the axis A to indicate the relative position of the pedal 104 corresponding to the operational state.

[0046] Also, the hydraulic damper 130 includes a controller 200 (i.e., sometimes referred to as an engine control unit 200, or ECU 200) that is electrically coupled to each of the two-way valve 176 of the fluid valve 170, the fluid pressure sensor 180, the temperature sensor 183, and the pedal position sensor 190. The controller 200 is configured to interpret signals from at least one of the fluid pressure sensor 180, the temperature sensor 183, and the pedal position sensor 190, corresponding to a hydraulic fluid pressure and temperature in the second fluid line 156 and corresponding to the relative position of the pedal 104 in one of the operational states and corresponding to the movement of the pedal 104 between operational states as directed by the user, to control the relative positioning of the two-way valve 176 within the fluid valve 170. In certain embodiments, the controller 200 is configured to interpret signals from at least the pedal position sensor 190 corresponding to the operational state of the pedal 104 (at any given instant and during the movement of the pedal 104 towards or away from the first and second operational states), while in further embodiments the controller 200 is configured to also interpret signals from the fluid pressure sensor 180 and / or the temperature sensor 183 (in addition to the signal from the pedal position sensor 190).

[0047] In the embodiments illustrated in FIGS. 1-7, the controller 200 is illustrated as being contained within a controller housing 201 affixed to, or otherwise integrally formed with, the base portion 103 of the pedal assembly 100. However, in other embodiments, the location of the controller 200 may be elsewhere in the variable resistance pedal assembly 100 or can be remotely mounted elsewhere in the vehicle. Alternatively, as shown in FIG. 8, the controller 200A could be located in a different portion of the controller housing 201 located in proximity to the pedal (for ease of illustration in FIG. 8, electrical connections from the controller 200A are omitted).

[0048] The subject disclosure also provides an associated method of use of the variable resistance pedal assembly as described above in a vehicle to control the vehicle. The method includes the steps of: applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states, measuring the pedal position of the pedal using the pedal position sensor at the second one of the plurality of operational states; measuring the temperature of the fluid using the temperature sensor at the second one of the plurality of operational states; and using the controller to adjust a valve position of the fluid valve to the chosen valve position at the second one of the plurality of operational states based at least on the measured pedal position and the measured temperature of the fluid during said step of applying force to pivot the pedal.

[0049] In certain embodiments, the method also includes the step of measuring the pressure of the fluid using the fluid pressure sensor at the second one of the plurality of operational state, wherein the controller adjusts a valve position of the fluid valve to the chosen valve position at the second one of the plurality of operational states also based on the measured fluid pressure.

[0050] Accordingly, when in use and in conjunction with the method described above, when the machine operator / user applies force to the top side 106 of the pedal 104 (shown by force arrows Fl in FIGS. 5A-5C) in an effort to slow down or stop the vehicle in embodiments where the pedal 104 is part of a braking assembly (or to accelerate the vehicle in an alternative embodiment by way of a second example when the pedal 104 is part of the accelerator assembly in a vehicle), as best shown in shown in FIG. 5A, the pedal 104 pivots (shown as Pl in FIGS. 5A-5B) about an axis A defined by the shaft 108 from a first one of the plurality of operational states to a secondone of the plurality of operational states. During this pivoting movement, the bottom side 105 of the pedal 104 acts on the push rod 162 to move the piston 164 within the piston chamber 152 towards the lower end of the piston chamber 152 adjacent to the opening of the second fluid line 156 and against the force of the coil spring 163 that is compressing during this piston 164 movement. The pivoting movement of the pedal 104 also acts upon the torsion spring 120 wrapped around the shaft 108 to compress the torsion spring 120. Collectively, the compression, respectively, of the torsion spring 120 and the coil spring 163 provide an increasing level of resistive force (z.e., a proportionally increasing amount of resistive force combined from the torsion spring 120 and coil spring 163) acting on the bottom side 105 of the pedal 104 against the force applied by the user to rotate the pedal 104 from the first to the second operational state.

[0051] When the two-way valve 176 is open (z.e., when the valve 176 is in fully open (i.e., the opened valve position as illustrated in FIGS. 4, 5A-C, 6-8 and 10A) or a partially open position (i.e., one of the intermediate valve positions as shown in FIG. 10B)), the piston 164 movement towards the lower end of the piston chamber 152 causes the hydraulic fluid 146 to be pushed out of the piston chamber 152 and into the first end 157 of the second fluid line 156 (see FIGS. 5A- C). The hydraulic fluid 146 then flows (see arrow 300 in FIGS. 5A and 5B) from the second end 159 of the second fluid line 156 through the fluid inlet line 172, the two-way valve 176, and through one or more fluid outlet lines 174, 174A-D of the fluid valve 170. The hydraulic fluid 146 then leaves the fluid outlet line 174D, passes through the ring shaped channel 175, through the opening 178 in the chamber housing 151 and reenters the reservoir chamber 150.

[0052] The relative flow rate of the hydraulic fluid 146 through the two-way valve 176 at a given force Fl applied by the user to the pedal 104, and hence between the piston chamber 152 to the reservoir chamber 150, is proportional to the degree of openness of the two-way valve 176, with a maximum flow rate occurring when the two-way valve 176 is fully open with the flow rate decreasing proportionally as the two-way valve 176 is moved towards a closed position (the pedal movement is illustrated with the user applying force to move the pedal 104 from the first operational state (FIG. 5 A illustrates the positioning of the pedal 104 at precisely the moment it leaves the first operational state)) through a plurality of intermediate operating positions (one intermediate position is shown in FIG. 5B) to the second operational state (FIG. 5C illustrates the positioning of the pedal 104 at precisely the moment it enters the second operational state). The resistive force of the hydraulic fluid 146 within the second chamber 152 provides a supplementalresistive force (in addition to the force of the torsion spring 120 and coil spring 163) to control the relative rate of pivoting of the pedal 104, and hence the associated rate of braking of the braking system to slow down or stop the vehicle in one embodiment or the associated rate of acceleration of the vehicle in another embodiment. The adjustment to reduce the resistive force of the hydraulic fluid 146 to maintain the pedal position at a particular operational state for a certain period of time, by opening the two-way valve 176, can reduce the foot fatigue a user / operator of the vehicle may experience by reducing the relative amount of force (Fl) that the user / operator applies to the top side 106 of the pedal 104 at the given operational state. This advantage is particularly relevant in cold weather conditions, wherein the current hydraulic fluid 146 temperature reduction results in a thickening of the hydraulic fluid 146 and increased resistive force of the hydraulic fluid 146 at the given operational state.

[0053] Conversely, when the pedal 104 is released by the user, as best shown in FIG. 6 in one of the intermediate positions (corresponding to the intermediate position illustrated in FIG. 5B), the coil spring 163 pushes the piston 164 back against the push rod 162 and away from the first end 157 of the second fluid line 156, with the push rod 162 applying force to the bottom side 105 of the pedal 104. At the same time, the torsion spring 120 applies force to the bottom side 105 to assist the push rod 162 in pivoting the pedal 104 in the opposite rotational direction (shown as P2 in FIG. 6)such that the pedal 104 returns to its first operational state. Collectively, these two forces are shown by arrow F2 acting on the bottom side 105 of the pedal 104 as shown in FIG. 6. As the pedal 104 moves towards the first operational state, a proportionally decreasing amount of resistive force is applied on the bottom side 105 of the pedal 104 contributed by the torsion spring 120 and coil spring 163, and a proportionally decreasing amount of resistive force is applied against the piston 164 and the push rod 162 by the coil spring 163 as the push rod 162 moves away from the lower end of the piston chamber 152. The hydraulic fluid 146 flows in a reverse manner during the piston’s 164 return stroke corresponding to the flow restriction of the hydraulic fluid 146 passing through the two-way valve 176 (which is in a fully-opened position) (the reverse flow is shown by arrow 320 in FIG. 6 which illustrates the flow of fluid 146 through the opening 178 in the chamber housing 151, through the ring-shaped channel 175, through the plurality of fluid outlet lines 174, 174A-D, through the two-way valve 176, through the fluid inlet line 172, through the second fluid line 156 and reentering the piston chamber 152). Further, hydraulic fluid 146 moves from the first chamber 150 through the first fluid lines 154A and 154B and into the space 169defined between the piston seals 166, 168 (this flow is shown by arrows 330 and 340 in FIG. 6). From between the piston seals 166, 168, the fluid 146 then flows around the lower seal 168 to fill a space 179 between the lower seal 168 and the first end 157 of the second fluid line 156 (this flow is shown by arrow 350 in FIG. 6). In particular, the lower seal 168 is flexible to move away from the cylinder wall 152A defining the second chamber 152 and allow fluid 146 to pass between the cylinder wall and the lower seal 168 and back into the space 179. Conversely, the lower seal 168 does not allow fluid 146 to flow in the opposite direction (i.e., from the space 179 into the space 169), and thus the lower seal 168 acts functionally as a one-way valve in addition to a seal.

[0054] The opening and closing of the two-way valve 176, to allow or prevent hydraulic fluid 146 flow through the valve 170, is controlled by the controller 200 based upon signals received from the pedal position sensor 190 regarding the relative operational state of the pedal 104, optionally from signals received from the fluid pressure sensor 180 regarding the hydraulic fluid 146 pressure in the fluid system 140, and signals received from the temperature sensor 183 regarding the temperature of the hydraulic fluid 146. The pedal 104 effort increases with increasing restriction caused by the movement of the two-way valve 176 towards a more closed intermediate valve position to decrease hydraulic fluid flow between the piston chamber 152 and the reservoir chamber 150 through the valve 176 to require more force to pivot the pedal 104 between operational states. Conversely, the pedal 104 effort decreases with decreasing restriction caused by the movement of the two-way valve 176 towards a more open intermediate valve position to increase fluid flow between the piston chamber 152 and the reservoir chamber 150 through the valve 176 to require less force be applied to pivot the pedal 104 between operational states.

[0055] The controller 200 dynamically adjusts the two-way valve 176 restriction to match a pre-programmed fluid pressure versus pedal position curve / map contained in the computer program of the controller 200. In other words, the controller 200 chooses a valve position to provide a desired amount of resistive force against the movement of the pedal 104 at a measured pedal position as determined by the pedal position sensor 190. Notably, there may be multiple pre-programmed maps provided within the controller 200 that can individually be selected on-the- fly by the user or by the vehicle's ECU during changing vehicle operating conditions. The use of these pre-programmed fluid pressure versus pedal position curve / map allows the resistive force on the pedal 104 to be preset across the entire operating range of pedal travel from the first operationalstate to the second operational state to provide the desired tactile feedback to the user operating the vehicle and in particular applying force to the pedal 104.

[0056] The pedal assembly 100 in accordance with the subject disclosure provides communication between the pedal 104 and the machine operator / user by dynamically altering the pedal resistance and / or travel of an X-by-wire system in real-time in response to inputs from the vehicle controller 200 and / or sensors 180, 190. In the absence of an external overriding input to the controller 200 by the user to select as desired one of the possible pre-programs, the pedal assembly 100 follows a predetermined pre-programmed hydraulic pressure throughout the pedal's 104 range of travel such as illustrated in FIG. 11 and / or through a pre-programmed pedal force curve throughout the pedal's 104 range of travel such as illustrated in FIG. 12.

[0057] Exemplary curves are illustrated in FIGS. 11 and 12 that include three different preprogrammed maps that factor in both hydraulic pressures and spring force (shown by reference lead lines 280, 282, 284) as compared with spring force only graphs (shown by reference lead line 286 and the diamond icon)) in which no fluid resistance is provided. In particular, reference lead line 280 in each of FIGS. 11 and 12 (also shown by square legend icon) represents a linear progression of the valve 170 closing across the span of 0% and 80% of pedal 104 travel, going between fully open at 0% travel to full closed at 100% pedal travel. Reference lead lines 282 and 284, respectively (also shown by circular and triangular icons in FIGS. 11 and 12), are non-linear curves that more closely represent how a normal brake pedal 104 feels to a user / operator. A maximum pressure curve would be a straight line across the pressure graph at the maximum pressure (about 158 psi in FIG. 11). This represents the valve 170 being fully closed across the entire range of pedal 104 travel.

[0058] In certain embodiments, as shown in FIGS. 11 and 12 in each of the representative maps, the controller 200 is pre-programmed to adjust the degree of openness of the two-way valve 176 in the non-linear or linear rate described above, thereby allowing the amount of flow of hydraulic fluid through the valve 176 between the piston chamber 152 and the fluid reservoir chamber 150 as described above in each of the operational states from the first operational state through the intermediate operational states to the second operational state as well as when the pedal is at rest in any of the operational positions. Accordingly, the increase in pedal 104 force to move between the operational states, caused by the increase in compression of the coil spring 163 against the force of the push rod 162 and piston 164 moving towards the lower end of the pistonchamber 152 adjacent to the opening of the second fluid line 156 and also due to the increase in force of the ends 124, 126 of the torsion spring 120 against the pivoting of the pedal 104 and the increase in force of the loop 125 of the torsion spring 120 against the base portion 103 of the pedal housing 102, can be adjusted to a desired degree of resistive force applied to the pedal 104 according to the pedal position / curve map balanced by the adjustment of the two-way valve 176 to a more opened position or a more closed position in accordance with any one of the preprogramed maps selected by the user / operator. As noted previously, the adjustment to reduce the resistive force of the hydraulic fluid 146 to maintain the pedal position at a particular operational state for a certain period of time, at the determined fluid temperature, by opening the two-way valve 176, can reduce the foot fatigue a user / operator of the vehicle may experience by reducing the relative amount of force (Fl) that the user / operator applies to the top side 106 of the pedal 104 at the given operational state.

[0059] In particular, if the combined resistive force owing to the combination of the compression of the coil spring 163 and torsion spring 120, in combination with the hydraulic fluid force within the piston chamber 152 acting on the piston 164, measures below the desired force according to the pre-programmed map utilized at the current pedal 104 position as measured by the pedal position sensor 190, when factoring in the hydraulic fluid 146 pressure and temperature as measured by the pressure sensor 180 and temperature sensor 183, the controller 200 will direct the two-way valve 176 to a more closed position. In this manner, the force of the hydraulic fluid 146 acting upon the piston 164 increases such that the total force matches the pre-programmed map at the particular operational state according to FIGS. 11 or 12. This maintenance of the consistent total force corresponding to a particular operational state provides the user / operator with a degree of assuredness and confidence that applying the vehicle is operating in a repeatable manner when braking or accelerating at the given operational state.

[0060] Conversely, if the combined resistive force owing to the combination of the compression of the coil spring 163 and torsion spring 120 and the hydraulic force within the piston chamber 152 acting on the piston 164 measures above the desired force according to the preprogrammed map utilized at the current pedal 104 position as measured by the pedal position sensor 190, when factoring in the hydraulic fluid pressure and temperature as measured by the pressure sensor 180 and temperature sensor 183, the controller 200 will direct the two-way valve 176 to a more opened position. In this manner, the increased flow rate of hydraulic fluid 146 outof the lower end of the piston chamber 152 will decrease the hydraulic fluid pressure within the piston chamber acting against the piston 164, which decreases the resistive force applied to the bottom side 105 of the pedal 104 against the user applied force as the measured pedal 104 position. In this manner, the force of the hydraulic fluid 146 acting upon the piston 164 decreases such that the total force matches the pre-programmed map at the particular operational state according to FIGS. 11 or 12.

[0061] In certain alternative representative maps, the controller 200 is programmed to keep the two-way valve 176 in the opened position for a first portion of the rotational travel of the pedal 104, such as a first percentage of the pedal 104 travel (i.e., pivot), from the first operational state to one of the intermediate operational states, thereby allowing the maximum flow of hydraulic fluid through the valve 176 between the piston chamber 152 and the fluid reservoir chamber 150 as described above.

[0062] In other words, the pre-programmed maps are not necessarily continually using the preprogramming to adjust the position of the two-way valve during the first 20% of the pedal 104 travel from the first operational state towards the second operational state. Instead, the increase in pedal 104 force against the operator applied force during the first 20% of the pedal 104 travel is therefore caused almost exclusively by the increase in compression of the coil spring 163 against the force of the push rod 162 and piston 164 moving towards the lower end of the piston chamber 152 adjacent to the opening of the second fluid line 156 and also due to the increase in force of the ends 124, 126 of the torsion spring 120 against the pivoting of the pedal 104 and the increase in force of the loop 125 of the torsion spring 120 against the base portion 103 of the pedal housing 102. The force against the travel of the piston 164 towards the lower end of the piston chamber 152 caused by the hydraulic fluid 146 in the lower end of the piston chamber 152, and hence the resistive force applied to the pedal 104 against the operator applied force contributed by the hydraulic fluid 146 pressing against the piston 164, is minimized because the hydraulic fluid 146 is allowed to freely be removed from the piston chamber 152 through the second fluid line 156 through the fully opened two-way valve 176. Beyond the 20% travel, the controller 200 would then adjust the positioning of the two-way valve 176 in accordance with the pre-programmed maps in the same manner as described above in FIGS. 11 and 12.

[0063] The subject disclosure also provides for a failsafe mechanism for assisting the user. In particular, if the pedal assembly 100 should fail with the two-way valve 176 in the closed position,or otherwise when fluid pressure is too high in the second fluid line 156 of the fluid system 140 even when the valve 176 is fully or partially opened, a mechanical pressure relief valve 158 contained in the bypass line 161 will open to allow the hydraulic fluid 146 to bypass the fluid valve 170 and flow (see dashed fluid arrow 311 in FIGS. 5C and 6, added as being representative of the flow path even though the valve 158 is closed as depicted and flow of the hydraulic fluid 146 is not permitted) between the piston chamber 152 and the reservoir chamber 150 through the bypass line 161.

[0064] In certain embodiments, the controller 200 is electronically connected to the haptic motor 112. In these embodiments, in addition to dynamically adjusting the two-way valve 176 restriction to match a pre-programmed fluid pressure versus pedal position curve / map, the controller 200 is also preprogramed to provide an electrical signal to the haptic motor 112 to vibrate under particular situation when the machine operator / user is in contact with the pedal 104, thus providing a tactile feel to the user.

[0065] This disclosure provides advantages over typical pedal assemblies for vehicles in that the variable resistance pedal assembly described herein utilizes an electro-hydraulic method for dynamically changing the pedal effort used on a vehicle. The arrangement described in the subject disclosure is similar to a brake or clutch master cylinder. The pedal assembly in accordance with the subject disclosure provides communication between the pedal and the machine operator / user by dynamically altering the pedal resistance and / or travel of an X-by-wire system in real-time in response to inputs from the vehicle ECU and / or sensors. In the absence of an external overriding input to the controller, the pedal assembly follows a pre-programmed pedal force curve throughout the pedal's range of travel. The pedal assembly is intended to be used for accelerator, brake, clutch, or to otherwise implement control in the off-highway, agriculture, and construction equipment markets, or any other suitable market or vehicle.

[0066] Several configurations have been discussed in the foregoing description. However, the configurations discussed herein are not intended to be exhaustive or limit the disclosure to any particular form. The terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations are possible in light of the above teachings and the disclosure may be practiced otherwise than as specifically described.

Claims

CLAIMS1. A variable resistance pedal assembly for use in a vehicle, comprising: a pedal moveable between a plurality of operational states including a first operational state, a second operational state and an infinite number of intermediate operational states between said first operational state and said second operational state; a hydraulic damper to dynamically control an effort of said pedal in one or more of said operational states and during one or more movements between said operational states, said damper comprising: a fluid housing defining a fluid system through which a fluid moves as said pedal moves between said plurality of operational states, said fluid system including a first chamber fluidically coupled to a second chamber, a fluid temperature sensor having a sensor housing defining a fluid inlet fluidically coupled to said fluid system, and a fluid valve moveable between an opened valved position and a closed valved position and a plurality of intermediate valve positions between said open valve position and said closed valve position, said fluid valve fluidically coupled to said fluid system; a push rod defining a length between a first end and a second end with said first end coupled to said pedal and said second end disposed within said second chamber of said fluid system; a pedal position sensor coupled to said pedal and configured to measure a relative position of said pedal in each of said plurality of operational states; and a controller electrically coupled to each of said fluid valve, said fluid temperature sensor, and said pedal position sensor with said controller pre-programmed with one or more programs to choose a valve position for said fluid valve based upon at least a measured pedal position from said pedal position sensor that correlates to an operational state from said plurality of operational states, said chosen valve position selected from said opened valved position, said closed valved position or one of said plurality of intermediate valve positions to dynamically control said effort of said pedal by controlling the flow of fluid through said fluid system.

2. The variable resistance pedal assembly according to claim 1, wherein said controller chooses said valve position also based upon at least a measured temperature of said fluid in said fluid system from said temperature sensor.

3. The variable resistance pedal assembly according to claim 1 or claim 2, wherein said hydraulic damper further comprises a fluid pressure sensor coupled to said fluid system and electrically coupled to said controller, wherein said controller chooses said valve position also based upon at least said measured pressure of said fluid from said fluid pressure sensor.

4. The variable resistance pedal assembly according to claim 1 further comprising a torsion spring coupled to said pedal and biasing said pedal towards said first operational state.

5. The variable resistance pedal assembly according to claim 4 further comprising a coil spring engaging said push rod within said second chamber and biasing said pedal towards said first operational state.

6. The variable resistance pedal assembly according to any one preceding claim, wherein said push rod includes a piston sealingly contained within said second chamber.

7. The variable resistance pedal assembly according to any one preceding claim, wherein said fluid system further comprises a plurality of fluid lines fluidically coupling said first and second chamber.

8. The variable resistance pedal assembly according to claim 7, wherein one or more of said fluid pressure sensor, said fluid valve and said temperature sensor are fluidically coupled to said plurality of fluid lines.

9. The variable resistance pedal assembly according to claim 7 or claim 8, wherein said plurality of fluid lines comprises a first fluid line and a second fluid line each separately fluidically coupling said first chamber to said second chamber.

10. The variable resistance pedal assembly according to any one preceding claim, wherein said fluid valve includes a fluid inlet line and a fluid outlet line separated by a two-way valve with said two-way valve moveable between said opened valved position and said closedvalved position and said plurality of intermediate valve positions between said open valve position and said closed valve position.

11. The variable resistance pedal assembly according to claim 10, wherein said fluid housing includes a chamber housing, and further including an opening in said chamber housing, and wherein said fluid outlet line of said fluid valve is fluidically connected to said first chamber through said opening in said chamber housing.

12. The variable resistance pedal assembly according to any one preceding claim, wherein said fluid system comprises a bypass line fluidically coupling said first chamber and said second chamber while bypassing said fluid valve, and a mechanical pressure relief valve contained within said bypass line configured to open when a fluid pressure in said bypass line exceeds a fluid pressure threshold value to allow said fluid to flow between said first chamber and said second chamber through said bypass line.

13. The variable resistance pedal assembly according to claim 9, wherein a pivoting movement of said pedal in a direction towards said second operational state causes said push rod to move towards a lower end of said second chamber, and wherein movement of said push rod towards said lower end of said second chamber causes said fluid to move from said second chamber into said second fluid line.

14. The variable resistance pedal assembly of claim 13, wherein movement of said push rod towards said lower end of said second chamber proportionally increases an amount of resistive force of said coil spring applied against said push rod.

15. The variable resistance pedal assembly according to claim 9, wherein a pivoting movement of said pedal in a direction towards said first operational state causes said push rod to move away from said lower end of said second chamber, and wherein the movement of said push rod away from said lower end of said second chamber causes said fluid to move from said first chamber to said second chamber through said first fluid line.

16. The variable resistance pedal assembly of claim 15, wherein the movement of said push rod away from said lower end of said second chamber proportionally decreases an amount of resistive force of said coil spring applied against said push rod.

17. The variable resistance pedal assembly according to any one of claims 9 to 16, wherein said fluid valve includes a fluid inlet line and a fluid outlet line separated by a two-way valve with said two-way valve moveable between said opened valved position and said closed valved position and said plurality of intermediate valve positions between said open valve position and said closed valve position, and wherein said fluid inlet line is fluidically coupled to said second fluid line.

18. The variable resistance pedal assembly according to any one preceding claim further comprising a shaft mounted to said housing with said pedal mounted to said shaft for concurrent rotation, and an end of said shaft disposed in said pedal position sensor for measuring rotation of said shaft.

19. The variable resistance pedal assembly according to any one of claims 3 to 18, wherein said fluid pressure sensor is contained in said sensor housing with said temperature sensor.

20. The variable resistance pedal assembly according to any one preceding claim, wherein said chosen valve position by said controller provides a desired resistive force against movement of said pedal at said measured pedal position.

21. A method of use of a variable resistance pedal assembly in a vehicle to control the vehicle, the variable resistance pedal assembly according to any one of claims 1 to 20, said method comprising: applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states, measuring the pedal position of the pedal using the pedal position sensor at the second one of the plurality of operational states;measuring the temperature of the fluid using the fluid temperature sensor at the second one of the plurality of operational states; and using the controller to adjust a valve position of the fluid valve to the chosen valve position at the second one of the plurality of operational states based at least on the measured pedal position and the measured temperature of the fluid during said step of applying force to pivot the pedal.

22. The method according to claim 21, wherein said step of applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states comprises: applying force from a user to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states in a direction away from the first operational state.

23. The method according to claim 21, wherein said step of applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states comprises: applying force from the coil spring and the torsion spring to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states in a direction away from the second operational state.

24. The method of any one of claims 21 to 23, further comprising said step of selecting one of the one or more programs; and wherein said step of using the controller to adjust a valve position for the fluid valve to the chosen valve position at the second one of the plurality of operational states based at least on the measured pedal position during said step of applying force to pivot the pedal comprises: using the selected one of the one or more programs of the controller to adjust a valve position for the fluid valve to the chosen valve position at the second one of the plurality of operational states during said step of applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states.

25. The method of any one of claims 21 to 24 further comprising said step of measuring the pressure of the fluid using the fluid pressure sensor at the second one of the plurality of operational states, wherein said step of using the controller to adjust a valve position for the fluid valve to the chosen valve position at the second one of the plurality of operational states based at least on the measured pedal position and the measured temperature of the fluid during said step of applying force to pivot the pedal comprises: using the controller to adjust a valve position for the fluid valve to the chosen valve position at the second one of the plurality of operational states based at least on the measured pedal position, the measured fluid pressure, and the measured fluid temperature during said step of applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states.

26. The method according to any one of claims 21 to 25, wherein a movement of the fluid valve in a direction towards the opened position during said step of applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states increases the flow of fluid through the fluid valve, and wherein a movement of the fluid valve in a direction towards the closed position during said step of applying force to pivot the pedal from a first one of the plurality of operational states to a second one of the plurality of operational states decreases the flow of fluid through the fluid valve.

27. The method according to any one of claims 21 to 26, wherein the fluid system further includes a bypass line fluidically coupling the second chamber to the first chamber that bypasses the fluid valve, and a mechanical pressure relief valve contained within the bypass line, and wherein said method further comprises: opening the mechanical pressure relief valve when the fluid pressure in the fluid system exceeds a fluid pressure threshold value to allow fluid to flow between the second chamber and the first chamber through the bypass line.

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