Brake system having a locking device and method of operating a brake system - Patents.com

Abstract

A brake system (100) comprising a brake caliper (102), a brake piston (118) supported by the brake caliper, brake pads (104, 106) supported by the brake caliper, a rotary-to-linear stage conversion mechanism (126), a motor (136) configured to drive the rotary-to-linear stage conversion mechanism to move the brake piston and move the brake pads against a brake rotor to generate a clamping force, and a locking device (146) configured to maintain a position of the rotary-to-linear stage conversion mechanism after the clamping force is generated, the locking device comprising a bistable solenoid (148). The motor is located on one side of the rotary-to-linear stage conversion mechanism and the locking device is located on another side of the rotary-to-linear stage conversion mechanism.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 346,490, filed May 27, 2022, the entire contents of which are incorporated herein by reference for all purposes.

[0002] These teachings relate to braking systems and methods of operating braking systems. [Background technology]

[0003] Many vehicles have one or more braking systems to generate a clamping force to slow, stop, and / or maintain the vehicle in a stopped or park position. Summary of the Invention [Problem to be solved by the invention]

[0004] It would be desirable to improve upon the state of the art by having an improved braking system and / or an improved method of operating a braking system. For example, it would be desirable to have a braking system and / or a method of operating a braking system configured to reduce or minimize the likelihood of premature release of clamping force. It would be desirable to have a braking system and / or a method that includes improvements over the state of the art to ensure or improve the rapid and efficient production of changes in clamping force. [Means for solving the problem]

[0005] A braking system is disclosed. The braking system may utilize one or more motors and one or more actuators to generate a clamping force during a braking event. The braking event may be applying a service brake, applying a parking brake, or both. The braking system may operate to generate the clamping force without hydraulic fluid. The braking system may be an electromechanical braking system.

[0006] A method for operating a brake system is disclosed. The method may be used to operate a brake system that may be a brake system according to these teachings. However, in some configurations, the method disclosed herein may be used to operate a brake system that is a variation of the brake system disclosed herein. In some configurations, the method disclosed herein may be used with other brake systems not exactly shown and / or described herein.

[0007] The braking systems and / or methods disclosed herein may advantageously improve braking performance by improving clamping force generation, improving clamping force maintenance after generation, and / or improving clamping force release. The braking systems and / or methods include improvements in clamping force maintenance to reduce or minimize the likelihood of premature clamping force release. The braking systems and / or methods include improvements in pre-charging to ensure that clamping force can be generated quickly and efficiently. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of the brake system and brake rotor. [Figure 2] FIG. 2 is a perspective view of the brake system. [Figure 3] 3 is a cross-sectional view of the brake system of FIG. 2 taken along line 3-3. [Figure 4]FIG. 2 is a cross-sectional view of the actuator and the rotary-to-linear stage conversion mechanism. [Figure 5] FIG. 5 is an exploded perspective view of FIG. 4. [Figure 6A] FIG. 1 is a perspective view of a locking device. [Figure 6B] FIG. 6B is an exploded perspective view of the locking device of FIG. 6A. [Figure 6C] FIG. 6B is an exploded perspective view of the locking device of FIG. 6A. [Figure 7A] FIG. 10 is a side view of the locking device in a disengaged position. [Figure 7B] FIG. 10 is a side view of the locking device in an engaged position. [Figure 8A] FIG. 2 is a cross-sectional view of an exemplary latching solenoid in an unlatched position. [Figure 8B] FIG. 2 is a cross-sectional view of an exemplary latching solenoid in a latched position. [Figure 9] FIG. 1 illustrates a field-oriented control (FOC) method for a motor. [Figure 10] FIG. 1 illustrates a speed-based control method for a motor. [Figure 11] FIG. 1 illustrates a position-based control method for a motor. [Figure 12] FIG. 1 illustrates a motor force controller having a force feedback component and a feedforward component. [Figure 13] FIG. 1 illustrates a motor force controller with force decay estimation. [Figure 14] FIG. 1 illustrates the method steps associated with the brake system entering a precharge state. [Figure 15] FIG. 1 illustrates method steps associated with operation of the brake system during service braking. [Figure 16] FIG. 1 illustrates the method steps associated with generating a clamping force or applying a parking brake. [Figure 17] 17A-17C illustrate method steps associated with releasing the clamping force generated in FIG. 16. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1, 2, and 3 illustrate a brake system 100. The brake system 100 includes a brake caliper 102 that supports an inboard brake pad 104 and an outboard brake pad 106. The brake caliper 102 may include a support bracket 103 that supports the brake pads 104, 106. In some configurations, the support bracket 103 may be considered part of the brake caliper 102, or in other configurations, the support bracket 103 may be a component attached to the brake caliper 102. The brake system 100 includes a support bracket 108 for mounting the brake system 100 and / or the brake caliper 102 to a vehicle, such as the vehicle's steering knuckle.

[0010] Brake system 100 is shown in Figure 1 with respect to brake rotor 110. Brake rotor 110 has an inboard side 112 and an opposing outboard side 114. After brake system 100 is installed on a vehicle, the friction material of inboard brake pad 104 faces the inboard side 112 of brake rotor 110, and the friction material of outboard brake pad 106 faces the outboard side 114 of brake rotor 110.

[0011] 3 , the brake caliper 102 includes one or more cylinders or bores 116. A brake piston 118 is supported within each cylinder or bore 116. High performance and / or heavy vehicles, such as pickup trucks and utility vehicles, may have brake calipers 102 with two or more bores 116, and therefore two or more brake pistons 118, to generate a clamping force sufficient to slow, stop, and / or impede movement of the vehicle. On the other hand, light-duty vehicles may have brake calipers 102 with only one bore 116, and therefore only one brake piston 118, that may be sufficient to generate a clamping force to slow, stop, and / or impede movement of the vehicle.

[0012] Braking system 100 may have one or more bores 116 and corresponding pistons 118 located on one side of brake rotor 110, such as the outboard or inboard side. In other configurations, braking system 100 may have one or more bores 116 and corresponding pistons 118 located on both sides (i.e., the inboard and outboard sides) of brake rotor 110.

[0013] A piston seal 120 and a dust boot 122 may be provided between the outer surface of the brake piston 118 and the inner surface or diameter of the bore 116. The piston seal 120 may be a flexible or resilient material or member that assists in returning or pushing the brake piston 118 back into the bore 116 after applying the brakes (to release the braking and / or clamping force). The dust boot 122 may be a flexible or resilient material or member that forms a seal around the brake piston 118. The dust boot 122 may limit or prevent debris and / or fluid from entering the space between the bore 116 and the brake piston 118.

[0014] Referring now to FIG. 4 , the brake system 100 may include an actuator 124. The actuator 124 may be used to move a rotary-to-linear stage mechanism 126, which may in turn move one or more brake pistons 118 and brake pads to generate and / or release a clamping force. Some or all of the elements of the actuator 124 may be contained within a housing 200 ( FIG. 2 ). The housing 200 may be attached to the brake caliper 102. Attaching the housing 200 to the caliper 102 may allow the actuator 124 to be assembled in a separate line or facility and then assembled or attached to the caliper 102 in another line or facility. This may allow the brake system 100 to be easily serviced if repair or maintenance of the actuator 124 or the brake system 100 is required. This may allow one supplier or manufacturer to build or assemble the actuator 124 and then provide it to a customer in the housing 200 for assembly into the brake caliper 102, or vice versa. The housing 200 may be attached to the caliper 102 by one or more fasteners (screws, bolts, welding, etc.). In some configurations, the housing 200 may be an integral component of the brake caliper 102 or may be permanently secured thereto by welding or other attachment methods. In some configurations, a portion of the housing 200 may be fixed to or integrated with the caliper 102, but may include a door or other access area that can be removed or opened to access the internal components of the brake system 100 or actuator 124 for inspection and / or service. During assembly of the brake system 100, the actuator 124 may be contained within the housing 200 and then connected to the rotary-to-linear stage conversion mechanism 126, which may be pre-installed in the brake caliper 102.

[0015] The rotary-to-linear stage mechanism 126 may be an assembly or mechanism located downstream of the actuator 124. However, in some configurations, the rotary-to-linear stage mechanism 126 may be part of the actuator 124 (and optionally be contained within the housing 200).

[0016] The rotary-to-linear stage mechanism 126 is a mechanism configured to convert a rotational input torque into a linear output force. The rotational input torque may be supplied to the rotary-to-linear stage mechanism 126 by the actuator 124 and / or by one or more motors 136. The linear output force may be used to move the brake piston 118 and / or structure of the brake system, and thus the inboard brake pad 104, toward and ultimately against the inboard side 112 of the brake rotor 110 to generate a clamping force. The rotary-to-linear stage mechanism 126 may be a high-efficiency device such as a ball nut assembly, a ball ramp assembly, a roller screw assembly, or the like. In some configurations, the rotary-to-linear stage mechanism 126 may be a low-efficiency device such as a lead screw and nut assembly. Of course, depending on the configuration of the brake system 100, the rotary-to-linear stage mechanism 126 may (additionally or alternatively) be arranged to move a brake piston located on the outboard side of the brake rotor, which in turn moves the outboard brake pad against the brake rotor to generate a clamping force.

[0017] 3 and 4, the rotary-to-linear stage conversion mechanism 126 includes a spindle 130 and a nut 132. The illustrated rotary-to-linear stage conversion mechanism 126 is a ball-nut assembly. A plurality of balls 134 may be disposed within tracks, grooves, or slots defined between the spindle 130 and the nut 132.

[0018] 3, brake system 100 may include retainer or clip 135, retainer or spring 137, thrust bearing 139, and force sensor or transducer 141. Force sensor or transducer 141 may provide force feedback (or feedback force) to the controller during brake application and / or brake release (application or release of service brakes and / or application or release of parking brakes), as discussed further below in the method of operating a brake system. That is, force sensor 141 may detect and send information to the controller indicative of how much clamping force (if any) is present based on the amount of force the nut exerts against the brake piston, which exerts force on the brake pad, which exerts force against the brake rotor to generate the clamping force. Although the force sensor is shown sandwiched between the thrust bearing 139 and the back of the bore that houses the brake piston, the force sensor 141 may be located anywhere in the brake system 100, such as between the nut and the brake piston, between the brake piston and the brake pad, between the brake pad and the brake rotor, etc. There may be more than one force sensor 141 in the brake system 100 to improve the accuracy of the force measurement and / or to provide a back-up or safety sensor.

[0019] The actuator 124 may include a motor-gear unit 128. The actuator 124 and / or the motor-gear unit 128 may include one or more motors 136. The motor 136 may be any device configured to generate and supply torque to the motor-gear unit 128 and / or the actuator 124. The motor 136 may be a brushless motor. The motor 136 may have an integrated rotational position sensor 138. Alternatively, the brake system 100 may have a rotational position sensor 138 that is separate from the motor 136. The rotational position sensor 138 is configured to detect and transmit the rotational or angular position of the output shaft 140 or output gear 144 of the motor 136. In some configurations, the position sensor 138 may instead be configured to determine the position of a brake piston, brake pads, a nut, a spindle, a rotary-to-linear translation mechanism, and / or one or more gears of the brake system 100. This rotational position sensor 138 can detect the rotational or angular position of the output gear 144 of the motor 136 and / or the rotational or angular position of the spindle 130, which can be used to determine the axial position of the piston 118. Knowing the axial position of the piston 118 can determine how much clamping force (if any) is being generated depending on the axial position of the nut, brake piston, and therefore the brake pads, relative to the brake rotor.

[0020] The actuator 124 and / or the motor gear unit 128 may include one or more gears 142. The one or more gears 142 may be disposed between the motor 136 and the rotary-to-linear stage conversion mechanism 126. The one or more gears 142 may be a gear train configured to transmit or provide torque from the motor 136 to the rotary-to-linear stage conversion mechanism 126. More specifically, the one or more gears 142 may transmit torque from the motor 136 to the spindle 130. The one or more gears 142 may function to increase, decrease, or simply transmit without increasing or decreasing the torque output from the motor 136 before the torque is provided to the rotary-to-linear stage conversion mechanism 126 or the spindle 130. In other words, the one or more gears 142 or gear train may be adjusted to a specific gear ratio for a specific application. The one or more gears 142 may function to increase or decrease the speed and / or torque output from the motor 136 before torque is supplied to the rotary-to-linear stage mechanism 126 or the spindle 130. The one or more gears 142 may function to maintain the speed and / or torque output from the motor 136 until torque is supplied to the rotary-to-linear stage mechanism 126 or the spindle 130.

[0021] The brake system 102, the actuator 124, and / or the motor gear unit 128 may include one or more locking devices 146. The locking device 146 may be a device configured to maintain a clamping force after braking (service brake and / or parking brake) is generated. The locking device 146 may be a device configured to lock the rotary-to-linear stage translation mechanism 126 to prevent the spindle 130 and nut 132 from moving or driving backward and / or prematurely or unintentionally releasing the clamping force. The locking device 146 may be a device configured to limit or prevent the brake piston 118 from pushing back after the clamping force is achieved. The locking device 146 may be a device that maintains the clamping force and / or the position of the brake pads pressed against the brake rotor after the clamping force is generated. The locking device 146 may be a device that maintains the angular or rotational position of a motor output shaft or gear. The locking device 146 may be a device that maintains the angular or rotational position of one or more gears 142 in a gear train or motor gear unit.

[0022] In some configurations, one or more of the locking devices 146 may be configured to lock or maintain the brake system from generating a clamping force. In other words, the locking devices 146 may be configured to lock or maintain the position of the motor to prevent the motor and / or rotary-to-linear stage translation mechanism from prematurely engaging or moving the brake piston. The one or more locking devices may be configured to prevent premature engagement or generation of a clamping force.

[0023] The locking device 146 may include one or more solenoids 148 , one or more clutch assemblies 150 , and one or more gears, such as an output gear 152 .

[0024] 4 , the motor 136 is located on one side of the rotary-to-linear stage conversion mechanism 126 (and thus on one side of the brake piston and bore within the brake caliper), and the locking device 146 is located on the other side of the rotary-to-linear stage conversion mechanism 26 (and thus on the other side of the brake piston and bore within the brake caliper). This arrangement advantageously allows the weight or mass of the motor 136 and locking device 146 to be evenly balanced and / or distributed over the brake caliper 102 and pin, rather than overloading one side and / or one pin if the motor 136 and locking device 146 were located on the same side of the brake caliper 102. This arrangement also allows for different gear ratios (i.e., different numbers, types, and / or sizes of gears 142) between the motor 136 and rotary-to-linear stage conversion mechanism 126 and the locking device 146 and rotary-to-linear stage conversion mechanism 126. Having different gear ratios may allow for independent adjustment of rotational fluctuations and loads on the locking device 146 during parking brake application without affecting the gear ratio of the motor 136 to the rotary-to-linear stage mechanism 126.

[0025] As can be seen in FIG. 4 , the motor output 140 of the motor 136 is configured to rotate about axis A, the spindle 130 is configured to rotate about axis B, the nut 132 is configured to move along axis B, and the mating member 190 and gear 152 of the locking device 146 are configured to rotate about axis C. Two or more of the axes A, B, and C (but preferably all three of the axes A, B, and C) are generally parallel to one another. Furthermore, the spacing between the axes A and B may be substantially the same as the spacing between the axes B and C. Such equal spacing between adjacent axes A, B, and B, C advantageously achieves equal mass distribution of the elements of the brake system 100 on the brake caliper 102, improving the performance of the brake system 100. However, in some configurations, the spacing between the axes A and B may be smaller or larger than the spacing between the axes B and C. It should be understood that the location of the motor 136 may be swapped with the location of the locking device 146 (i.e., the motor 136 may be located where the locking device 146 is located, or the locking device 146 may move to where the motor 136 is currently located). In some configurations, the motor 136 may be located on top of or next to the locking device 146, or vice versa. In some configurations, the locking device 146 may be integrated with the motor 136 so as to be a single device.

[0026] To initiate braking, or to initiate application while applying the service brakes and / or the parking brakes, one or more signals may be sent or transmitted to brake system 100, motor 136, actuator 124, or a combination thereof. The signals may be sent by a controller 300 ( FIG. 2 ) operable to control motor 136. Controller 300 may be part of brake system 100, the vehicle, or both. The one or more signals may command motor 136 to turn on and / or begin generating torque. Torque from motor 136 is transmitted to rotary-to-linear stage conversion mechanism 126 via one or more gears 142. More specifically, referring to FIG. 5 , torque from motor 136 is transferred to gear 156 by meshing engagement of motor output gear 144 and gear 156, thereby rotating gear 156 and gear 158. Gear 158 may be rotationally fixed to gear 156, meaning that when one of the gears rotates, the other gear also rotates. Gear 158 engages gear 160, thereby rotating gear 160 and gear 162. Gears 160 and 162 may be rotationally fixed, meaning that when one of the gears rotates, the other gear also rotates. Gear 162 engages gear 164, rotating gear 164 and sun gear 166. Sun gear 166 is surrounded by a plurality of planet gears 168, which are positioned inside internal gear 170, which has a toothed profile on its inner periphery. Planet gears 168 are positioned on respective axles 172 supported between carriers or plates 174, 176. Rotation of sun gear 166 causes planet gears 168 to spin about their respective axles 172 and also rotate within internal gear 170 about axis B, thereby causing carriers 174, 176 to rotate about axis B. Carrier 176 includes an engagement portion 178 configured to engage with a corresponding engagement portion 180 of spindle 130. Rotation of carrier 174 causes spindle 130 to rotate about longitudinal axis B.Rotation of spindle 130 about axis B causes nut 132 to translate or move linearly along the length of spindle 130 and / or along the length of longitudinal axis B of spindle 130. Nut 132 is moved along spindle 130 until the air gap between the nut and brake piston is absorbed and nut 132 contacts brake piston 118, subsequently pushing brake piston 118 and then inboard brake pad 104 against the inboard side 112 of brake rotor 110. In a sliding brake system such as that shown in the illustration, this then generates a retracting force that causes bridge and finger 202 to slide on the sliding pin, pulling outboard brake pad 106 against the outboard side 114 of brake rotor 110. The friction material of brake pads 104, 106 contacts brake rotor 110, creating friction and thereby generating torque to slow, stop, or impede the movement of brake rotor 110 and, therefore, the main wheels. In an alternative or fixed braking system that does not include a moving or sliding bridge, brake pistons located on either side of the brake rotor may be engaged with or moved by a similar rotary-to-linear stage conversion mechanism such as that shown and described herein. One or more of the aforementioned gears may be eliminated or duplicated. For example, a non-limiting example of this is that gear 144 may engage gear 162.

[0027] Gears 166, 168, 170 and carriers 174, 176 may form a planetary gear system. The planetary gear system may function to increase torque, decrease torque, or maintain constant torque output from motor 136. The planetary gear system may function to increase output speed of motor 136, decrease output speed of motor 136, or maintain constant output speed of motor 136. The planetary gear system may be adjusted to change the gear ratio to ensure sufficient torque is supplied to the rotary-to-linear stage conversion mechanism. In some configurations, the planetary gear system may be omitted. In configurations where a gear is omitted, motor output 144 may directly drive rotary-to-linear stage conversion mechanism 126. In some configurations, one or more gears may be added to gear 142 as shown and / or disclosed herein. In some configurations, one or more of the gears 142 shown and / or disclosed herein may be relocated, repositioned, or substituted with other gears or mechanisms for transmitting torque from the motor 136 to the rotary-to-linear stage mechanism 126, the brake piston, and / or the brake pads.

[0028] 5 , the brake system 100 and / or the actuator 124 may include a locking device 146. The locking device 146 may be part of the brake system 100, or the locking device 146 may be part of the actuator 124, or the locking device 146 may be an independent device that is not part of either the brake system 100 or the actuator 124 but is assembled onto the system 100 as a separate component. The locking device 146 may be configured to lock the actuator 124 to limit or prevent the rotary-to-linear mechanism 126 and / or the motor and / or the brake piston 118 from pushing back or driving backward after a clamping force is generated after applying the service brakes, applying the parking brakes, or both. The locking device 146 may include a solenoid 148, a clutch assembly 150, and a locking device output gear 152. The locking device output gear 152 is in meshing engagement with a gear 164. By meshingly engage is meant that the teeth of one gear engage with the teeth or sockets between the teeth of another gear. Other methods of engagement may also be considered, including intermediate gears, belts, chains, or toothless gears that frictionally engage with each other.

[0029] 6A, 6B, and 6C show the locking device 146. The locking device 146 may include a solenoid 148, a clutch assembly 150, and a locking device output gear 152.

[0030] Solenoid 148 may be any solenoid, such as a bistable solenoid. A bistable solenoid is an electromechanical magnet having a linear direction of motion in which a movable member 182 or piston or plunger is moved between a retracted, unlocked, or disengaged position (FIG. 7A) and an extended, locked, or engaged position (FIG. 7B). As shown in FIG. 5, axis C may be parallel to axis B.

[0031] The movable member 182 or piston of the locking device 146 or solenoid 148 is connected to an engagement member 184 that includes teeth 186. The engagement member 184 is supported in a bracket 188 or yoke. The engagement member 184 has an anti-rotation feature 199 that cooperates with a corresponding or mating anti-rotation feature in the bracket 188 or yoke to limit or prevent the engagement member 184 from rotating or spinning about the longitudinal axis C of the locking device 146. The anti-rotation feature 199 may be any suitable feature, such as one or more pins, notches, flat or planar features, protrusions, set screws, indentations, keyed features, etc.

[0032] The locking device 146 includes a counter member 190. The counter member 190 may be a dog having cogs or teeth 192 configured to engage with cogs or teeth 186 of the engaging member 184 when the movable member 182 and the engaging member 184 are moved toward the counter member 190 along the longitudinal axis C. Once the teeth 186, 192 engage with one another (i.e., once the teeth fit within opposing sockets defined between adjacent teeth defined on the other member), the locking device 146 may be locked.

[0033] The counter member 190 is or includes one or more bearings 194. The bearings 194 allow the counter member 190 to rotate or spin about the longitudinal axis C. The rotation of the counter member 190 allows the locking device 146 to remain locked or engaged (i.e., the teeth 186, 192 of the engaging member 184 and the counter member 190 remain engaged) while the clamping force is adjusted, for example, during a re-clamping procedure.

[0034] Counterpart 190 is supported within an opening in bracket 196. The opening is sized to accommodate counterpart 190 and bearing 194 and to allow counterpart 190 to rotate within bracket 196 about axis C. Bracket 196 is U-shaped and has an arm 198 configured to engage a corresponding arm 200 on bracket 188 that supports movable member 182.

[0035] The locking device output gear 152 includes an engagement feature 204 configured to engage with a mating engagement feature 206 defined in the counter member 190. This engagement causes the counter member 190 to rotate about the longitudinal axis C when the output gear 152 is rotated about the longitudinal axis C, which may occur when the clamping force is adjusted or increased.

[0036] After the clamping force is generated, a signal may be sent from the controller to the locking device 146 to lock the brake system 100 to maintain the clamping force. The signal may be sent by a controller 300 (FIG. 2) operable to control one or both of the motor 136 and the solenoid 148 of the locking device 146. Preferably, the electronic control unit 300 is configured to control the motor 136 and the solenoid 148 independently.

[0037] Figure 7A shows the locking device 146 in an unlocked or disengaged position, and Figure 7B shows the locking device in a locked or engaged position. For clarity, brackets 188, 196 are hidden in these views.

[0038] 7A and 7B, one or more signals sent from the controller to the locking device 146 cause the movable member or plunger 182, and thus the engagement member 184, to move axially along axis C until the teeth 186 of the engagement member 184 engage or mesh with sockets defined between adjacent teeth 192 of the mating member or dog 190 (moving from the position in FIG. 7A to the position in FIG. 7B). The slope of the walls of the teeth 186, 192 is sufficiently steep to limit or prevent the mating member 190 and gear 152 from rotating in the release direction (see, e.g., the generally vertical slope on the teeth 184, 190 in FIGS. 7A and 7B). Once engaged, the locking device output gear 152 is limited or prevented from rotating about axis C in the release direction by engagement with the mating member 190 via engagement members 204, 206 (FIG. 6B). As discussed above, gear 152 is in meshing engagement with gear 164, thus limiting or preventing or impeding rotation of gear 164 about axis B (FIG. 5). Because gear 164 is restricted from rotating about axis B, rotary-to-linear stage mechanism 126 is locked and restricted from rotating about axis B, thus preventing brake piston 118 from pushing back, thereby maintaining brake pad 104 in contact with brake rotor 110. Thus, the motor can be turned off or can cease producing torque, and locking device 146 will maintain the actuator position, and therefore the clamping force.

[0039] If reclamping is necessary to adjust or increase the previously generated clamping force, one or more corresponding signals may be sent by electronic control unit 300 to actuator 124, motor 136, and / or drive portion 154, causing motor 136 to generate and transmit torque to linear-to-rotary mechanism 126 as discussed above. Locking device 146 may remain locked or engaged (e.g., remain in the position shown in FIG. 7B ) during this time. However, due to the engagement of locking device output gear 152 and gear 164, gear 152, and therefore mating member 190, may rotate about axis C in the braking direction when gear 164 is rotated by motor 136 in the braking direction. The low-angle slope of mating teeth 186, 190 allows gear 152 and mating member 190 to rotate about axis C in the braking direction while engagement member 184 remains fixed and not rotating. In other words, the mating member 190 can be incrementally rotated or clocked in the braking direction by sliding the teeth 192 up the ramp to the next position on the teeth 186 or socket of the engaging member 184 without releasing the clamping force.

[0040] 8A and 8B are cross-sectional views of an exemplary solenoid 148. The solenoid 148 is a latching solenoid. The solenoid in FIG. 8A is in an unlatched position 210. The solenoid in FIG. 8B is in a latched position 208.

[0041] The solenoid 148 may include a movable member or plunger 182, a coil 212, a spring 214, a permanent magnet 216, and a pole 218. The movable member or plunger 182 is connected to an engagement member 184 (see FIGS. 6B-6C and 7A-7B).

[0042] 6B-6C and 7A-7B, in the latched position 208 (FIG. 8B), the movable member or plunger 182 is in an extended position such that its engagement members 184 or teeth 186 are in engagement with the teeth 192 of the mating member or dog 190. That is, the teeth 186 of the engagement member 184 fit between or are positioned between the teeth 192 of the mating member. The spring 214 provides the necessary biasing force to push or bias the plunger 182 into the extended position such that the engagement members 184 and teeth 186 remain engaged against (more specifically, between) the teeth 192 of the mating member or dog 190. During a reclamping operation, the plunger 182 retracts slightly, compressing the spring 214, as the teeth 186 of the engagement member 184 ride over and traverse the ramp profile of the teeth 192 of the mating member or dog 190. The spring 214 then decompresses after the ramp profile of the teeth 192 of the mating member or dog 190 is traversed by the teeth 186 of the engagement member 184, further biasing the plunger 182 into the extended position shown in FIG. 8B.

[0043] 8A to release the locking member, the coil 212 is energized (by one or more signals from the controller 300) and the plunger 182 is moved axially against the spring 214, thereby compressing it until the plunger 182 latches onto the pole 218. During this energization phase, the total magnetic force is amplified as the sum of both the permanent magnet 216 and the electromagnetic effect. Upon reaching the unlatched state 210, the coil 212 is de-energized and the latching force is maintained solely by the permanent magnet 216.

[0044] To latch from the unlatched state 210, the coil 212 is energized with a reversed polarity that reduces the magnetic force until the spring 214 overcomes the magnetic latching force and then moves or biases or transitions the plunger 182 forward to the latched position 208 of FIG. 8B as described above. Once in the latched state 208, the coil 212 is de-energized and the latching force is maintained solely by the spring force from the spring 214.

[0045] The electronic control unit 300 contains the necessary hardware to control the polarity of the coil 212 and therefore brake engagement / disengagement.

[0046] Braking system 100 is operable and / or controllable by an electronic control unit 300. Electronic control unit 300 may be part of the vehicle, braking system 100, or both. Controller 300 is in electrical communication with braking system 100 and is operable to control both motor 136 and solenoid 148 of locking device 146. Preferably, electronic control unit 300 is configured to control motor 136 and solenoid 148 independently.

[0047] When a clamping force is applied (during service and / or parking brake application) to slow, stop, or prevent movement of the vehicle's main wheels, one or more of the foregoing or following method steps may be performed. It is understood that any method step disclosed herein may be omitted, duplicated, combined with another method step, or rearranged in a different order.

[0048] The method may include measuring the absolute rotational or angular position of the motor 136 or motor output shaft or gear. The absolute initial position of the motor 136 or output shaft 140 or motor output 144 may be measured or determined by the rotational position sensor 138 or any other sensor in the brake system 100 or vehicle. In some configurations, the rotational angular position of the spindle may be measured or determined by a sensor that measures the same.

[0049] The method may include modifying or incrementing the absolute initial position of the motor 136 or output shaft 140 or motor output 144 by rotary encoder counts for accurate displacement measurement from the absolute initial position. This may eliminate the need for an initialization routine to determine correct commutation in the case of incremental encoders. The position sensor 138 may also include redundant measurements of both the absolute position of the motor 136 or shaft 140 or output gear 144 and the incremental encoder signal for determining feedback reliability.

[0050] The brake system 100 may be controlled by current-based control via current from a power source such as a battery, motor, engine, or alternator. Current-based control may be achieved by the method shown in FIG. 9. The brake system 100 may be controlled by field-oriented control (FOC). The brake system 100 may include individual measurements of phase currents from the motor 136. A Clarke Transform (Clarke) may be used to transform the phase current measurements from the motor 136 into an alpha-beta frame. The position sensor 138 may provide feedback of the rotational angle (θ) of the output shaft 140 or motor output 144. This feedback is used to transform the fixed alpha-beta frame into direct (d), quadrature (q), and zero components in a rotating reference frame (dq) using a Park Transform (Park). Each of the feedback components may be compared to a command reference and transferred through a controller to determine a command voltage in the rotating dq frame. The controller may be a feedback control loop that calculates an error signal by obtaining the difference between the feedback component and a command reference or setpoint. Feedback of the rotor position angle (θ) or output shaft 140 or motor shaft 144 may be used to convert from the dq frame to the rotating alpha-beta frame using the inverse Park transform (inverse Park). Space vector pulse width modulation (SVPWM) may be used to calculate each of the individual phase voltages provided to the motor 136 from the electronic control unit 300.

[0051] The brake system 100 may be controlled by speed-based control of the motor 136 as shown in FIG. 10. A position sensor 138 may provide closed-loop speed feedback to a reference command. The calculated error may be provided to the controller for calculation of a quadrature current that is forwarded to the speed controller. Correspondingly, position-based control may be achieved by adding an additional position reference that is forwarded to the speed control as shown in FIG. 11. In both cases, field weakening may be implemented by commanding a non-zero Id reference when increased speed / position response is required. Implementation is typically achieved by logical or experimental lookup of Id_ref.

[0052] The brake system 100 may be controlled by force-based control of the motor 136. Closed-loop force control may be achieved by a force sensor transducer 141. Force measurements are compared to a command for quadrature current correction. Such correction may provide disturbance compensation for brake torque variations during braking (parking or service), for example, due to DTV or actuator degradation. When the force has a direct relationship to both the MGU torque and the corresponding quadrature current, a feedforward component can be provided based on actuator dynamics. Due to the back-drive effect of the rotary-to-linear stage translation mechanism 126, a feedforward component may be required to maintain a steady-state load condition as the feedback approaches the command target. The force transducer 141, which may be located in the caliper assembly 102, actuator 124, motor 136, etc., may include redundant measurements to provide a reliable means of determining between the two signals. If the force feedback is determined to be unreliable, a force estimation means can be provided based on the measured position of the motor output or shaft and the motor current according to defined actuator dynamics.

[0053] 14 illustrates method steps associated with the brake system 100 entering a precharge state 408. The precharge state 408 may refer to or indicate a position of the brake system 100 where any gap defined between the nut 132 and the brake piston 118 is absorbed or reduced to zero. The precharge state 408 may refer to or indicate a position of the brake system 100 where any gap defined between the brake piston 118 and the brake pads is absorbed or reduced to zero. The precharge state 408 may refer to or indicate a position of the brake system 100 where any gap defined between the brake pads and the brake rotor is absorbed or reduced to zero. The precharge state 408 may refer to or indicate a position of the brake system 100 where a gap or clearance within a specified tolerance exists between the nut 132 and the brake piston 118, between the brake piston 118 and the brake pads, and / or between the brake pads and the brake rotor. The precharge state 408 may refer to or refer to a position of the brake system 100 that generates essentially no clamping force. The precharge state 408 may occur before the service brakes are applied, the parking brakes are applied, or both.

[0054] From the released state 400, the brake system 100 can enter a precharge state 408, where essentially no clamping force is present. In the released state 400, one or more brake pads are not in contact with the brake rotor. In the released state 400, a gap or space is defined between the nut 132 and the brake piston 118. In other words, the nut 118 is not exerting a pushing or compressing force on the brake piston 118, the brake piston 118 is not exerting a pushing or compressing force on the brake pads, and therefore the brake pads are not exerting a pushing or compressing force on the brake rotor and therefore are not generating a clamping force.

[0055] A command 402 may be provided to the brake system 100 by a controller 300 associated with the brake system 100 and / or the vehicle to enter the pre-charge state 408. The request or command 402 may be in response to a braking intent, such as a user or operator depressing the brake pedal, slowing the vehicle, a user pressing a button, a verbal command, or the vehicle detecting an obstacle or obstruction in its path. Upon receiving the pre-charge request or command 402, the air gap between the nut 132 and the brake piston 118 is absorbed or reduced to zero by operating the motor 136 to generate torque to operate the actuator 124, thereby rotating the spindle 132 and thus moving the nut 132 into contact with the brake piston 118. Thus, after receiving the pre-charge request or command 402, the air gap defined between the brake pad and the brake rotor is absorbed or reduced to zero. Air gaps between the nut 132 and the brake piston 118 and / or between the brake pads and the brake rotor may be accommodated by velocity-based control 404 or position-based control. Velocity-based control 404 may be preferred over position-based control because it may achieve the pre-charge state 400 more quickly than position-based control.

[0056] The brake system 100 may achieve the pre-charge state 408 after a value meets or exceeds a threshold value in step 406. The threshold value may be a time value, a force or pressure value, a current value, a position value, or a combination thereof. For example, in certain configurations, the threshold value may be a time value (when using velocity-based control), a current value (when using current-based control), a force or pressure value (when using force-based control), or a position value (when using position-based control). However, in some configurations, one or more of the threshold values ​​(time, force or pressure, current, position) may be used for any type of control (velocity-based control, current-based control, force-based control, position-based control). After the value meets or exceeds the threshold value 406, the brake system 100 enters the pre-charge state 408.

[0057] FIG. 15 illustrates method steps 500 related to operation of brake system 100 during service braking. Of course, one or more of these steps may also be utilized during parking braking. The method of FIG. 15 begins by determining whether the brake system is in pre-charge state 408 (see FIG. 14). After controller 300 determines that brake system 100 is in pre-charge state 408, controller 300 or brake system 100 may then check or determine, in step 502, whether a clamping force command or instruction exceeds or exceeds a threshold or hold-off value. If the command or instruction exceeds the hold-off value 502, method 500 transitions to force-based control 504 to generate a clamping force to slow, stop, or maintain the vehicle in a stationary position. Again, the clamping force is generated by nuts 132 pressing brake pistons 118 against brake pads, which in turn press brake pads against the brake rotor.

[0058] In the event that a signal or command 506 is sent to the controller 300, if the brake command value is less than the holdoff value, for example, if the vehicle operator removes his or her foot from the brake pedal, the method 500 may transition back to and wait in the precharge state 408 ( FIG. 14 ). Finally, when a release command 508 is received, for example, by the user depressing the accelerator pedal, the method 500 transitions to position-based control 510, where the actuator 124 is moved to define an air gap between the brake pads and the brake rotor, and between the nut 132 and the brake piston 118.

[0059] FIG. 16 shows a method 600 for generating a clamping force or applying the parking brake. Of course, this method may also, or instead, be used to apply the service brakes. The parking brakes may be applied at any time as long as the vehicle is stationary or not moving 602. This means that the vehicle can be in the precharge state 408 (FIG. 14) while the brake pedal is depressed or while clearance exists between the nut 132 and the brake piston 118 and / or between the brake pads and the brake rotor.

[0060] After a command 604 is received to apply the parking brake (e.g., by a user turning off the vehicle, pressing a button or lever, voice command, etc.), method 600 may transition to force-based control in step 606, which generates a clamping force until the measured force exceeds a threshold target force. This force feedback may be generated by force sensor 141 or any other sensor in brake system 100. After the measured force meets or exceeds the threshold target force, method 600 may transition to position-based control 610 to hold the clamping force. A timer may be started in step 612 to ensure the clamping force is held for a sufficient time before locking device 146 is activated in step 614 to hold and maintain the clamping force. If another timer exceeds a threshold in step 616, the parking brake remains applied in step 618, and the FOC or motor may be disabled.

[0061] FIG. 17 illustrates method steps 700 associated with releasing the clamping force generated in FIG. 16. The method begins with the vehicle in park or generating a clamping force 618 (FIG. 16). After a command or instruction 702 is received to release the clamping force (e.g., by a user or operator turning on the vehicle, depressing the accelerator pedal, pressing a button or lever, verbal command, etc.), the method 700 may transition to force-based or position-based control 704 by turning on a motor and generating additional clamping force to relieve the load on the locking device 146 and unload or unlock 706 the locking device 146. After the method 700 or the controller 300 determines that the locking device 146 is unloaded at 708, a timer may be set to ensure the locking device 146 is sufficiently unloaded, and the method 700 may transition to force-based or position-based control 712 to set an air gap or running clearance between the brake pads and the brake rotor. Alternatively, after method 700 or controller 300 determines that locking device 146 is unloaded at 708, a timer may be set to ensure locking device 146 is fully unloaded, and method 700 may transition to force-based control if the command is above a holdoff value or threshold, a precharge state if the command is below a holdoff value or threshold, or a released clearance state if commanded according to FIG. 15.

[0062] The brake systems disclosed herein may be service brake systems. The brake systems disclosed herein may be parking brake systems. The brake systems may be combined service and parking brake systems. The brake systems may not use fluid or hydraulic fluid to pressurize and move one or more brake pistons to generate and / or maintain a clamping force. In some configurations, the brake systems may use fluid or hydraulic fluid to pressurize and move one or more brake pistons for one or more brake application functions (i.e., service brake and / or parking brake). In some configurations, the brake systems may use fluid or hydraulic fluid to generate a clamping force during one brake application function (i.e., for service brake application) and an electromechanical system for another brake application function (i.e., parking brake), or vice versa.

[0063] A brake system may be a system or assembly for generating or releasing a clamping force. The clamping force may be a force that, when combined with the coefficient of friction of the brake pad friction material, functions to slow, decelerate, stop, and / or prevent movement or rotation of the brake rotor, main wheels, and / or vehicle. The clamping force may be used during service braking operations to slow, stop, and / or maintain the vehicle in a stopped position. The clamping force may be used during parking braking operations to maintain the vehicle in a stopped or parked position. The clamping force may be used during both service and parking braking operations.

[0064] The clamping force creates an energy transfer by converting the vehicle's kinetic energy into thermal energy by frictionally engaging one or more brake pads with one or more sides of the brake rotor. The one or more brake pads may include one or more features (i.e., ears, protrusions, etc.) that engage or can be engaged by the brake caliper, the support bracket, or both to maintain the brake pad's location within the brake system and relative to the brake rotor.

[0065] The one or more brake systems may be incorporated into a vehicle, which may be a passenger car or truck, a heavy-duty vehicle such as a cargo truck or construction dump truck, a racing car, a motorcycle, an off-road vehicle, a utility vehicle, an all-terrain vehicle (ATV), a utility vehicle (UTV), or the like.

[0066] The brake system may include a brake caliper. The brake caliper may function to support brake system components, including one or more brake pads, one or more brake pistons, one or more motors, one or more MGUs, one or more locking devices, one or more rotary-to-linear stage conversion mechanisms, or a combination thereof. The brake system may be made of a suitable material, such as metal, iron, steel, aluminum, plastic, composite, or a combination thereof. The brake caliper may be made by a casting process, a molding process, a milling process, or a combination thereof. The brake caliper may be made of a one-piece structure. The brake caliper may be manufactured by two or more parts, or halves, that are later joined together by one or more fasteners (bolts, screws, welding, etc.).

[0067] The braking system may include one or more brake pads. One or more of the brake pads disclosed herein may be positioned on an inboard side of the brake rotor, and one or more of the brake pads may be positioned on an outboard side of the brake rotor. The brake pads may be supported on or by a brake caliper. The brake pads may be supported on or by a support bracket connected to the brake caliper.

[0068] The brake pad may have a pressure plate and friction material. The friction material may be moved against the side of the brake rotor to generate friction to generate a clamping force. During application of the brakes (service and / or parking), the pressure plate may be pushed out by one or more brake pistons and / or retracted by one or more fingers or bridges of the caliper until the friction material is pressed against the brake rotor.

[0069] The brake system may have one or more brake pistons. The one or more brake pistons may be located on one side of the brake rotor (either on the inboard or outboard side of the brake rotor). The one or more brake pistons may be located on both sides of the brake rotor. The brake piston may have a hollow portion or pocket operable to receive at least a portion of a corresponding rotary-to-linear stage conversion mechanism. The brake piston pocket may be a cup or recess formed in an end of the brake piston. The brake piston pocket may include a bottom wall at the end or bottom of the brake piston pocket and an opposite open end. A clearance gap may exist between a nut of the rotary-to-linear stage conversion mechanism and the corresponding bottom wall. During application of the brakes (service and / or parking), the clearance gap may be absorbed by moving the nut of the rotary-to-linear stage conversion mechanism toward the bottom wall. The nut may be moved by rotating the spindle with an actuator. Once the gap is absorbed, further movement of the nut or rotary-to-linear stage conversion mechanism can cause it to press against the bottom wall of the brake piston to generate a clamping force, which in turn moves the brake piston, and therefore the brake pads, against the brake rotor.

[0070] By moving the nut away from the bottom pocket wall, the brake piston can be moved in the opposite release direction, which allows the brake pad to subsequently move away from the brake rotor to release the clamping force. The brake piston can be retracted by a rotary-to-linear stage conversion mechanism. The brake piston can be pushed back by the elastic properties of one or more piston seals surrounding the brake piston.

[0071] The braking system may include one or more motors. The motor may be any motor for generating force or torque. For example, the motor may be a permanent magnet synchronous motor (PMSM) or an electrically excited synchronous motor (EESM). The motor may include one or more electrical leads, terminals, connections, or plugs for connecting the motor to a power source, a computer, a processor, and / or an electronic control unit. By supplying power to the motor, an output shaft or an output gear of the motor may rotate about an axis. Rotation of the output shaft may be oriented in a braking direction (to generate a clamping force) and a releasing direction (to release the clamping force). The braking direction may be clockwise and the releasing direction may be counterclockwise, or vice versa. The motor may be part of an actuator. The motor may be a separate component of the actuator. The motor may be included in a housing with the actuator. The motor may be included in a separate housing as the actuator.

[0072] The brake system may include one or more rotary-to-linear stage conversion mechanisms. The rotary-to-linear stage conversion mechanisms may function to convert torque output from a power source into linear or axial force to move one or more brake pistons. The power source may be one or more motors and / or actuators. The rotary-to-linear stage conversion mechanisms may be high-efficiency devices such as ball screws, roller screws, ball ramps, ball nut assemblies, and ball screw assemblies. The rotary-to-linear stage conversion mechanisms may also be low-efficiency devices such as lead screws, which have higher friction between the spindle and nut compared to high-efficiency devices.

[0073] The spindle may be rotated by a motor and / or an actuator and / or by one or more gears. The spindle may be rotated in an apply direction and a release direction to apply and release the brake system, respectively. Rotating the spindle may cause a nut threadably engaged with the spindle to move axially along the longitudinal axis of the spindle in the apply or release direction to move the brake pads toward or away from the brake rotor. The spindle may be directly driven by a motor or gears (a direct connection or attachment between two elements). The spindle may be indirectly driven by a motor or gears (an indirect connection or attachment between two elements, meaning that one or more gears, shafts, belts, chains, or other intermediate connecting members are provided between the spindle and the motor or gears).

[0074] The nut can be moved axially along the axis about which the spindle is configured to rotate. For example, the nut and spindle can be threadably engaged such that rotation of the spindle by a motor or drive gear causes the nut to move axially toward or away from the wall of the piston pocket. After contact is made between the nut and the piston pocket wall, further movement of the nut can result in the brake piston, and therefore the brake pad, or the corresponding end of the brake pad, moving toward the brake pad. The nut can be limited or prevented from rotating about the axis about which it is configured to move axially. That is, the nut may have a suitable anti-rotation feature that prevents the nut from rotating about the axis about which the spindle rotates.

[0075] When the rotary-to-linear stage conversion mechanism includes a ball screw, the rotary-to-linear stage conversion mechanism may have a plurality of balls between the spindle and the nut. The balls are contained within matching spiral grooves in the spindle and the nut, and the balls roll between the grooves to provide the only contact between the spindle and the nut. In some configurations, the rotary-to-linear stage conversion mechanism may not have any balls between the spindle and the nut.

[0076] The rotary-to-linear conversion mechanism may be part of the actuator. The rotary-to-linear conversion mechanism may be located downstream of the actuator. The rotary-to-linear conversion mechanism may be located in a housing and assembled within a brake caliper. The rotary-to-linear conversion mechanism may be installed within the brake caliper, and the actuator may then be installed or attached to the caliper and connected to the rotary-to-linear conversion mechanism.

[0077] The brake system may include one or more locking devices. The locking devices may function to lock or maintain the clamping force after it is generated. The locking devices may function to limit or prevent the motor, rotary-to-linear stage conversion mechanism, spindle, nut, brake piston, and / or brake pads from moving. The locking devices may function to limit or prevent the motor, rotary-to-linear stage conversion mechanism, spindle, nut, brake piston, and / or brake pads from driving backward after the clamping force is generated. The locking devices may function to maintain the rotational or linear position of the motor, rotary-to-linear stage conversion mechanism, spindle, nut, brake piston, and / or brake pads. The locking devices may function to maintain the clamping force. The locking devices may function to maintain the clamping force during clamp reactivation when the clamping force is adjusted or increased. The locking devices may function to maintain the clamping force even after the motor is disconnected or disengaged or no longer generates torque.

[0078] The locking device may be disengaged to allow release of the clamping force.The locking device may be disengaged to reduce the amount of clamping force generated during braking.

[0079] The locking device may be engaged only during application of the service brakes, only during application of the parking brakes, or during application of both the service and parking brakes.

[0080] The locking device may comprise one or more solenoids, which may include a bistable solenoid, a linear solenoid, a rotary solenoid, a DC solenoid (C or D frame), or the like.

[0081] A bistable solenoid may contain one or more electrochemical magnets with a linear direction of motion that locks the plunger or movable member into each extreme position. This can be achieved by splitting the coil equally at approximately the center and using the resulting air gap as a permanent magnet. A bistable rotary solenoid can be driven to rotate in either direction and hold in either extreme position with no power applied.

[0082] The locking device may include a dog clutch. The dog clutch may include a clutch or engagement member and a dog or mating member. The clutch and dog may each include mating male / female profiles, such as teeth that engage valleys defined between the teeth. The teeth may have slanted or angled walls and opposing generally vertical walls, thereby allowing the mating member to rotate relative to the fixed engagement member, or vice versa.

[0083] The clutch or engagement member may be a piston or plunger or may be connected to a piston or plunger that moves axially to engage or disengage the locking member. The piston or plunger or engagement member may move axially into engagement with the dog or mating member by reacting to a magnetic field generated by the solenoid when current is supplied to the solenoid and when it is not supplied to the solenoid. The clutch or engagement member may be limited or prevented from rotating. However, in some configurations, the clutch or engagement member may be configured to rotate. The dog or engagement member may be configured to rotate. The dog or mating member is limited or prevented from moving axially along the axis about which it rotates. However, in some configurations, the mating member may move axially along the axis.

[0084] The locking device may be part of the actuator. The locking device may be located downstream or upstream of the actuator. The locking device may be located within the housing and assembled within the brake caliper. The locking device may be located outside or external to the housing.

[0085] The locking device may be of the type disclosed in commonly owned U.S. Patent No. 11,136,010, filed February 7, 2019 as U.S. Patent Application No. 16 / 269,718, which claims priority to U.S. Provisional Patent Application No. 62 / 632,457, filed February 20, 2018, all of which are expressly incorporated by reference herein for all purposes.

[0086] The braking system may include one or more force sensors. The force sensor may function to convert a physical force into one or more electrical signals. The force sensor may be a load cell. The force sensor may be a sensor that converts an input mechanical load, weight, tension, compression, or pressure into an electrical output signal. The electrical output signal may be provided to an electronic control unit for use in the methods disclosed herein. The electrical output signal may be used to determine the amount of clamping force generated during or after braking. The force sensor may measure the amount of force acting on the brake pad (via the brake piston), the amount of force acting on the brake piston (via the nut), or a combination thereof. The force sensor may measure a reduction in force to generate an output signal. For example, when the nut is in a retracted position, a force may be applied to the force sensor. During braking, when the nut is moved toward the piston, pushing the piston, the force acting on the force sensor may be reduced, and this force may be correlated to the generated clamping force.

[0087] The electronic control unit may function to control the braking system. The electronic control unit may be part of the braking system or part of the vehicle. Each braking system may have its own control unit (i.e., left front wheel, right front wheel, left rear wheel, right rear wheel, etc.), or one electronic control unit may control two or more braking systems (front / rear or left / right). The control unit may be part of a vehicle controller. The control unit may include a processor, memory, and programs. The control unit may be programmable and reprogrammable. The control unit may control the motor and locking device together or individually. The control device may activate the locking device only during certain braking operations, such as while parking on a hill or slope. In other cases, the control device may activate the locking device during or after all braking events (service and / or parking brake).

[0088] A braking system according to these teachings may include one or more gears. Any gear disclosed herein may be replaced by two or more gears. Any two or more gears disclosed herein may be replaced by a single gear. One or more intermediate gears may be provided between any two or more gears disclosed herein that are directly meshed with one another. Any intermediate gear disclosed herein between two or more other gears may be omitted.

[0089] One or more of the gears may be part of the actuator, may be separate from the actuator, may be contained within the housing, may be located outside the housing, or a combination thereof.

[0090] Any gear disclosed herein may be a spur gear, a helical gear, a bevel gear, a worm gear, etc. Any gear disclosed herein may be replaced by a spur gear, a helical gear, a bevel gear, a worm gear, etc.

[0091] While the gears disclosed herein are described as having teeth that mesh or meshingly engage with other gears to transmit torque between the gears, it is understood that other means can be used to transmit torque, such as, for example, using one or more belts, chains, intermediate gears, shafts, racks and pinions, axles, etc. Furthermore, in certain applications, the teeth on one or more of the gears may be omitted, and the gears may engage each other by pressure or friction fit to transmit torque. Furthermore, any gear disclosed herein may be replaced by a shaft, belt, chain, or other torque transmission means. Furthermore, any of the gears and their orientations disclosed herein may be reconfigured and still fall within the scope of the present disclosure.

[0092] The gears disclosed herein may be made of any material, such as metal, plastic, 3D printed, etc. One or more gears may be made by casting or plastic injection molding processes.

[0093] Any of the gears, elements, or assemblies disclosed herein may be reconfigured so that a previously disclosed element that extends or moves along or rotates about an axis A, B, or C may extend, rotate, or move along another axis that may be parallel or non-parallel (i.e., perpendicular or at another angle) to any axis A, B, C.

[0094] Where one or more gears are described as rotating about a shaft or axis, one or more bearings and / or bushings may be provided at any contacting surfaces.

[0095] Various embodiments are disclosed herein. It is within the scope of this disclosure that elements of the embodiments may be combined, overlapped, or separated to form additional embodiments. Also, any element disclosed herein may be omitted from, overlapped with, and / or combined with other elements in any of the assemblies disclosed herein.

[0096] The descriptions and illustrations presented herein are intended to acquaint those skilled in the art with the invention, its principles, and its practical application. The above description is intended to be illustrative, not restrictive. Those skilled in the art may adapt and apply the invention in its numerous forms, as may be best suited to the requirements of a particular use.

[0097] Accordingly, the particular embodiments of the present teachings as described are not intended to be restrictive or limiting of the present teachings. Accordingly, the scope of the present teachings should be determined without reference to this description, but instead should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The omission in a claim of any aspect of the subject matter disclosed herein should not be construed as a disclaimer of such subject matter or as an indication that the inventors do not regard such subject matter as part of the disclosed inventive subject matter.

[0098] A single integrated element or step may provide multiple elements or steps. Alternatively, a single element or step may be divided into multiple separate elements or steps.

[0099] The disclosure of "a" or "one" to describe an element or step is not intended to exclude additional elements or steps. For example, the disclosure of "a motor" does not limit the teachings to a single motor. Instead, for example, the disclosure of "a motor" may include "one or more motors."

[0100] Terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used to distinguish one element, component, region, layer, or section from another region, layer, or section. Terms such as "first," "second," and other numerical terms, when used herein, do not imply an order or sequence unless clearly indicated by the context. Thus, a first element, component, region, layer, or section discussed below may be referred to as a second element, component, region, layer, or section without departing from the present teachings.

[0101] Spatially relative terms such as "inside," "outside," "below," "belower," "lower side," "upper," and the like may be used herein for ease of description to describe the relationship of one element or feature to another as shown in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures is turned upside down, elements described as "below" or "below" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may also be otherwise oriented (rotated 90 degrees or to other orientations), and the spatially relative descriptors used herein may be interpreted accordingly.

[0102] The invention illustratively disclosed herein may suitably be practiced in the absence of any element not specifically disclosed herein.

[0103] Any of the elements, components, regions, layers, and / or sections disclosed herein are not necessarily limited to a single embodiment. Instead, any of the elements, components, regions, layers, and / or sections disclosed herein may be substituted for, combined with, and / or modified by any of the elements, components, regions, layers, and / or sections disclosed herein to form one or more embodiments that may not be specifically shown or described herein.

[0104] The disclosures of all articles and references, including patent applications and publications, test specifications, are incorporated by reference for all purposes. Other combinations are also possible as derived from the claims, and these are also incorporated by reference into this written description.

Claims

1. In the brake system, Brake calipers and a brake piston supported by the brake caliper; a brake pad supported by the brake caliper or by a support bracket associated with the brake caliper; a rotary-to-linear stage conversion mechanism connected to the brake piston; a motor configured to drive the rotary-to-linear stage conversion mechanism to move the brake piston and move the brake pad against the brake rotor to generate a clamping force; a locking device configured to maintain a position of the rotary-to-linear stage translation mechanism after the clamping force is generated, the locking device comprising a bistable solenoid; A braking system, wherein the motor is supported on the brake caliper and is located on one side of the rotary-to-linear stage conversion mechanism, and the locking device is located on another side of the rotary-to-linear stage conversion mechanism.

2. The braking system of claim 1 , wherein the locking device comprises a dog clutch.

3. The braking system of claim 2 , wherein the dog clutch includes an engagement member that is restricted from rotating about an axis but configured to move along the axis.

4. 4. The braking system of claim 3, wherein the dog clutch includes a mating member configured to rotate about the axis but restricted from moving along the axis.

5. 5. The brake system of claim 4, wherein the engaging member is movable between an unlocked position and a locked position, wherein in the locked position the engaging member is engaged with the mating member and in the unlocked position the mating member is configured to rotate about the axis.

6. 6. A braking system according to claim 4 or 5, wherein the engaging member and the mating member include teeth, one or more of the teeth being angled.

7. The brake system according to claim 1 , wherein the rotary-to-linear stage conversion mechanism is located on an inner side of the brake rotor.

8. 6. The brake system according to claim 1, wherein the brake system comprises a plurality of gears between the motor and the rotary-to-linear stage conversion mechanism, the plurality of gears being arranged in a planetary gear system.

9. 6. A braking system according to any one of claims 1 to 5, wherein the motor has an output that rotates about an axis, the locking device has an output that rotates about an axis, and the spindle of the rotary-to-linear stage conversion mechanism rotates about an axis, all of the axes being substantially parallel to one another.

10. 10. The braking system of claim 9, wherein the spacing between the axis of the motor output and the axis of the spindle is approximately the same as the spacing between the axis of the spindle and the axis of the locking device.

11. 6. The braking system of claim 1, wherein the braking system is a floating caliper.

12. A brake system according to any one of claims 1 to 5, wherein the motor and / or the locking device are contained in a housing that is separate from the brake caliper.

13. The braking system of claim 12 , wherein the braking system includes a plurality of gears between the motor and the rotary-to-linear stage conversion mechanism, the plurality of gears being disposed within a planetary gear system and the housing.

14. 6. A method of operating a brake system according to any one of claims 1 to 5, a) using a motor and a rotary-to-linear mechanism to move a brake pad against a brake rotor to generate a clamping force; b) engaging a locking device to maintain the position of the rotary-to-linear stage translation mechanism after the clamping force is generated; The method wherein the braking system is controlled using field oriented control.

15. 15. The method of claim 14, including entering a precharge state, wherein an air gap between the nut and the brake piston is eliminated or optimized to reduce free-running time.

16. 16. The method of claim 15, including using velocity-based control to achieve the precharge state and then using force-based control to generate the clamping force.

17. 15. The method of claim 14, comprising releasing the clamping force by unloading the bistable solenoid and disengaging the locking device.

18. The method of claim 17 including using position-based control to set clearance between the brake pads and the brake rotor.

19. 15. The method of claim 14, wherein the method does not include the step of pressurizing hydraulic fluid to generate the clamping force.

20. The method of claim 14, wherein the brake system is controlled by current-based control.

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