WO2017056066A2

WO2017056066A2 - Vehicle braking system and method

Info

Publication number: WO2017056066A2
Application number: PCT/IB2016/055886
Authority: WO
Inventors: Christian Nolin
Original assignee: Bombardier Recreational Products Inc.; Brp Us Inc.
Priority date: 2015-09-30
Filing date: 2016-09-30
Publication date: 2017-04-06
Also published as: WO2017056066A3

Abstract

A method of braking a vehicle having a brake member operatively connected to a wheel and an actuation system operatively connected to the brake member to apply a force thereto. The brake member is actuated when the actuation system applies force thereto. The actuation system actuates the brake member to dispose the brake member in a braking configuration in a slowing state for braking of the wheel responsive to receiving a request for slowing the vehicle. Responsive to receiving a request for immobilizing the vehicle, the brake member is actuated with the actuation system so to be disposed in the braking configuration in a parking state in which the brake member prevents rotation of the wheel. The brake member disposed in the parking state is engaged with a parking lock to thereby prevent the brake member from moving out of the parking state. Braking systems are also disclosed.

Description

VEHICLE BRAKING SYSTEM AND METHOD CROSS-REFERENCE

[0001] The present application claims priority to United States Provisional

Patent Application No. 62/235,342 filed on September 30, 2015, the entirety of which is incorporated herein by reference.

FIELD OF TECHNOLOGY

[0002] The present technology relates to vehicle braking systems and methods.

BACKGROUND [0003] Vehicles having three or more wheels typically have a regular brake system for slowing down or stopping the vehicle while it is being operated and a parking brake system for preventing the vehicle from moving when it is parked. The regular brake system includes a regular brake operator, in the form of a foot-operated brake pedal or a hand-operated brake lever, that is typically connected to a hydraulic system for actuating brakes connected to one or more of the wheels of the vehicle. The parking brake system includes a parking brake operator, in the form of a button, switch, lever or the like, that is typically mechanically coupled to one of the wheels of the vehicle. These two braking systems with their multitude of components sometimes prove to be bulky and expensive to manufacture. [0004] FIG. 1 shows a vehicle 10 having a front end 2 and a rear end 4 defined consistently with the forward travel direction of the vehicle 10. The vehicle 10 has a frame 12 that supports other elements of the vehicle 10.

[0005] The vehicle 10 is a three-wheel vehicle 10 including a left front wheel

14 (not shown), a right front wheel 14 and a single rear wheel 16 connected to the frame 12. Vehicles having more than one rear wheel, or only one front wheel are also known. Each front wheel 14 is connected to the frame 12 by a front suspension assembly (not shown). The rear wheel 16 is connected to the frame 12 by a rear suspension assembly 20, which includes a swing arm 22 and a shock absorber 24. The left and right front wheels 14 and the rear wheel 16 each have a tire secured thereto.

[0006] As shown in FIG. 2, each of the two front wheels 14 and the rear wheel

16 is provided with a brake assembly 82. Each brake assembly 82 is a disc-type brake assembly mounted onto a hub of the respective wheel 14 or 16. Other types of brake assemblies, such as drum brake assemblies, are also known. The brake assemblies 82 are part of a braking system 80 for braking the vehicle 10 that will be described below in further detail. Operation of the braking system 80 is controlled by an electronic braking control system 110. [0007] With reference again to FIG. 1, the frame 12 supports a motor 30

(shown schematically in FIG. 1). In the vehicle 10 of FIG. 1, the motor 30 is an internal combustion engine. In some vehicles 10, the motor 30 is other than an internal combustion engine, for example, an electric motor, a hybrid, or the like. The engine 30 is operatively connected to the rear wheel 16 to drive the rear wheel 16. An engine control unit (ECU) 32 (shown schematically in FIG. 1) is connected to the engine 30 for controlling operation of the engine 30. In some vehicles 10, the ECU 32 includes a plurality of modules for controlling different aspects of the engine 30.

[0008] The vehicle 10 is a straddle-type vehicle having a straddle seat 40 supported by the frame 12. The straddle seat 40, which is adapted to accommodate two adult-sized riders, includes a forward seat portion 42 for the driver and a rearward seat portion 44 for a passenger. The rearward seat portion 44 is higher than the forward seat portion 42. The forward seat portion 42 is referred to hereinafter as the driver seat 42, and the rearward seat portion 44 is referred to hereinafter as the passenger seat 44. [0009] A driver footrest 46 (the right one of which can be seen in FIG. 1) is disposed on either side of the vehicle 10 and vertically lower than the straddle seat 40 to support the feet of a driver seated on the driver seat 42. The right driver footrest 46 is mounted on a right rail 47 connected to the frame 12. Although not shown, the left driver footrest is similarly mounted on a left rail connected to the frame 12. Each side of the vehicle 10 also has a passenger footrest 48 (the right one of which can be seen in FIG. 1) disposed rearward of the corresponding driver footrest 46 to provide support to the feet of the passenger seated on the passenger seat 44. The passenger footrests 48 are also mounted to the frame 12. In some vehicles 10, the footrests 46, 48 are in the form of footboards instead of footpegs as shown here.

[0010] A steering assembly 50 is disposed forwardly of the straddle seat 40 to allow a driver to steer the two front wheels 14. The steering assembly 50 includes a handlebar 52 connected to a steering column 54 such that the turning the handlebars 52 turns the wheels 14.

[0011] A start-up operator 56 is provided for starting or ending operation of the vehicle 10. The start-up operator 56 is connected to the control unit 32 for starting and ending operation of the vehicle 10. The start-up operator 56 is in the form of a button/key disposed forward of the straddle seat 40.

[0012] A gear-shift actuator (not shown), in the form of a foot-operated gear shift lever, is connected to the left driver footrest 46. The gear-shift actuator is operatively connected to a gear-shift selector of the transmission (not shown) of the vehicle 10 for selecting one of a plurality of gears. Some vehicles 10 have a hand- operated gear-shift actuator connected to the handlebars 52. In some vehicles 10, the gear-shift actuator is omitted, for example, in a vehicle 10 having an automatic transmission.

[0013] The vehicle 10 includes other components such as radiators, headlights, a fuel tank, and the like, some of which may be readily recognized by a person skilled in the art. These components however will not be discussed herein.

[0014] The braking system 80 of the vehicle 10 will now be described with reference to FIGs. 1 and 2. The braking system 80 includes the brake assemblies 82, a regular brake operator 60, a hydraulic actuation system 100 operatively connected thereto, a parking brake operator 62, and a parking brake actuation system 120 operatively connected thereto.

[0015] As can be seen in FIG. 2, each brake assembly 82 includes a rotor 84 and a caliper 86 that each include a pair of brake pads (not shown) for clamping their respective rotors 84. The rotor 84 is mounted onto the wheel hub and the stationary caliper 86 is mounted to the vehicle 10 so as to straddle the rotor 84. Each brake pad is disposed between the rotor 84 and the caliper 86 on either side of the rotor 84. When the brake pads are actuated, the rotor 84 is squeezed therebetween resulting in slowing or stopping of the rotation of the rotor 84, depending on the magnitude of force exerted on the brake pads, the rotational speed of the rotor 84 when the brake pads are pushed thereagainst and the length of time that force is applied. The brake pads of each of the wheels 14, 16 can be actuated by the hydraulic actuation system 100, and the brake pads of the rear wheels 16 can additionally be actuated by the parking brake actuation system 120 as will be described below.

[0016] The regular brake operator 60, in the form of a foot-operated brake lever, also referred to herein as brake pedal, is connected to the right driver footrest 46. The brake pedal 60 is operatively connected, via the hydraulic system 100, to the brake assemblies 82 provided on each of the two front wheels 14 and the rear wheel 16 for decreasing vehicle speed (slowing down or stopping the vehicle 10) while the vehicle 10 is operating. In some vehicles 10, the brake pedal 60 is operatively connected only to the brake assembly 82 of the front wheels 14, or only to the brake assembly 82 of the rear wheel 16. In some vehicles 10, the regular brake operator 60 is in the form of a hand-operated brake lever connected to the handlebar 52 instead of the foot-operated brake lever shown herein. It is also known to have both of the hand- operated and foot-operated forms of regular brake operator 60. The brake pedal 60 is used by the driver when the vehicle 10 is in operation to slow or stop the vehicle 10.

[0017] The hydraulic actuation system 100 includes a hydraulic fluid reservoir

106, a master cylinder 102 and hydraulic brake lines 104 that fluidly connect the master cylinder 102 with each caliper 86. Each caliper 86 includes a hydraulic cylinder (not shown) and a piston (not shown). Actuation of the brake pedal 60 by the driver results in actuation of the brake pads 316 via the master cylinder 102. Actuation of the brake pedal 60 first causes brake fluid to flow out of the master cylinder 102 towards the cylinders of the calipers 86, thereby causing brake fluid further downstream in the brake lines 104 to flow into the cylinder of each caliper 86, moving the corresponding piston and thereby moving the corresponding brake pad into contact with the rotor 84. Once the brake pad contacts the rotor 84, further actuation of the brake pedal 60 does not move the piston or brake pad, but rather, results in an increased hydraulic pressure on the piston which in turn applies an increased force on the corresponding brake pad towards the corresponding rotor, thereby increasing the friction between the brake pad and the corresponding rotor 84. Through friction, the brake pads slow the rotor 84 and thereby the respective wheels 14, 16. The hydraulic actuation system 100 also includes an electronically controlled hydraulic unit 108 positioned between the master cylinder 102 and the calipers 86. The electronically controlled hydraulic unit 108 includes a hydraulic pump, a manifold and a plurality of valves (all shown schematically as 108). The braking control unit 110 is connected to the valves of the electronically controlled hydraulic unit 108 to control how the hydraulic pressure from the master cylinder 102 and brake pedal 60 is distributed between the calipers 86 in order to maintain stability of the vehicle 10. The braking control unit 110 is further connected to the hydraulic pump of the electronically control hydraulic unit 108 to control the hydraulic pump to selectively apply pressure on each caliper 86 independently of, or in addition to, the master cylinder 102. [0018] The vehicle 10 is provided with the parking brake operator 62 which is used by the driver when the vehicle 10 is parked to request immobilization of the vehicle 10, i.e. to keep the vehicle at rest when it is parked. The parking brake operator 62 is therefore also referred to herein as the vehicle immobilization operator 62. The parking brake operator 62 is linked to the brake assembly 82 of the rear wheel 16 to actuate the brake assembly 82 for immobilizing the vehicle 10. In the vehicle 10 of FIG. 1, the parking brake operator 62 is provided in the form of a button mounted to the handlebars 52 which can be pressed to actuate the brake pads. The parking brake operator 62 controls an electric motor (not shown) that rotates a pulley 94. The pulley 94 is connected by a push-pull cable 92 to the brake assembly 82 of the rear wheel 16. The pulley 94 converts the rotary motion of the electric motor into linear translation of the cable 92. The cable 92 is connected to a parking brake actuator arm 90 for actuating the brake pads. The cable 92 can be pushed/pulled to move the actuator arm 90 between two positions. In a first position of the parking brake actuator arm 90, the parking brake actuator arm 90 exerts a force of the brake pads to push the brake pads to an engaged position where the brake pads push against the rotor 84 to prevent the rotor 84 from rotating. This is commonly referred to as "engaging a parking brake". In a second position of the parking brake actuator arm 90, the actuator arm 90 does not exert a force on the brake pads so that the brake pads are in a disengaged position relative to the rotor 84 and the rotor 84 is not prevented from rotating (in the absence of the brake pads being pressured by the hydraulic system 100). The parking brake cable 92 is actuated as described above in response to the pressing of the parking brake operator button 62. The electric motor is mounted to the vehicle frame 12 remotely from the rear wheel 16, and the cable 92 extends from the pulley 94 to the rear wheel 16. When the parking brake operator button 62 is pressed, the electric motor causes the parking brake actuator arm 90 to move from its current position in one of the first and second positions to the other of the first and second positons. The electric motor thus provides enough force to actuate the brake pads to an engaged position and to keep the brake pads in the engaged position while the vehicle 10 is parked. In some vehicles 10, the parking brake operator 62 is in the form of a lever that is directly connected to the parking brake cable 92 for mechanically actuating the parking brake actuation arm 90 by pulling on the lever.

[0019] Thus, in the braking system 80 of the vehicle 10 of FIGs. 1 and 2, the brake pads can be actuated by either of the hydraulic actuation system 100 and the parking braking actuation system 120. In the braking system 80 of Figs. 1 and 2, pressing the parking brake operator 62 actuates the brake pads of the rear wheel 16 independently of the hydraulic system 100. The electric motor of the parking brake actuation system 120 is of a sufficiently large size so as to be able to actuate the brake pads into engagement with the rotor 84 independently of the hydraulic system 100, and to keep the brake pads in a position pushing against the rotor 84.

SUMMARY

[0020] It is an object of the present technology to ameliorate at least some of the inconveniences mentioned above. [0021] In accordance with one aspect, there is provided a method of braking a vehicle. The vehicle includes a brake member operatively connected to a wheel of the vehicle and an actuation system operatively connected to the brake member and configured to apply a force thereto. The brake member is actuated when the actuation system applies the force thereto. The actuation system is configured to actuate the brake member to dispose the brake member in a braking configuration in a slowing state for braking of the wheel responsive to receiving a request for slowing the vehicle. The method includes, responsive to receiving a request for immobilizing the vehicle, actuating the brake member with the actuation system to dispose the brake member in the braking configuration in a parking state in which the brake member prevents rotation of the wheel and engaging the brake member disposed in the parking state with a parking lock to thereby prevent the brake member from moving out of the parking state.

[0022] In some implementations, the actuation system is caused to cease actuating the brake member while the brake member disposed in the parking state is engaged by the parking lock. [0023] In some implementations, a maximum force exertable by the parking lock on the brake member is less than the force applied on the brake member by the actuation system to dispose the brake member in the braking configuration in the parking state.

[0024] In some implementations, the actuation system comprises an actuation member which actuates the brake member. The actuation system applies the force on the brake member via the actuation member. The parking lock engages the actuation member, and thereby the brake member, to prevent the brake member from moving out of the parking state.

[0025] In some implementations, the parking lock is self-locking with respect to a force exerted by the brake member on the parking lock to prevent the brake member from moving out of the parking state.

[0026] In some implementations, the brake member is actuated along a brake actuation axis and the parking lock is actuated along a lock actuation axis to engage the brake member. The lock actuation axis is one of parallel to and coaxial with the brake actuation axis.

[0027] In some implementations, the step of stopping actuating the brake member while the brake member disposed in the parking state is engaged by the parking lock occurs responsive to an end operation of the vehicle being requested. [0028] In some implementations, responsive to receiving a request for stopping immobilization of the vehicle, the actuation system is caused to actuate the brake member to enable the brake member to be disposed in the parking state in the absence of the parking lock engaging the brake member. The parking lock is disengaged from the brake member while the actuation system actuates the brake member. The actuation system is caused to stop actuating the brake member after disengaging the parking lock from the brake member to allow the brake member to be disposed in a configuration other than the parking state.

[0029] In some implementations, stopping actuating the brake member comprises gradually decreasing the force applied by the actuation system on the brake member.

[0030] In some implementations, hydraulically actuating the brake member with the hydraulic actuation system comprises operating a hydraulic pump to apply the hydraulic force on the brake member. [0031] In accordance with another aspect, there is provided a method of braking a vehicle. The vehicle includes a brake member operatively connected to a wheel of the vehicle. An actuation system is operatively connected to the brake member and configured to apply a force thereto. The brake member is actuated when the actuation system applies the force thereto. A parking lock is selectively operatively connected to the brake member. Responsive to receiving a request for braking the vehicle for slowing the vehicle, the brake member is actuated with the actuation system to dispose the brake member in a braking configuration in a slowing state in which the brake member slows rotation of the wheel. Responsive to receiving a request for immobilizing the vehicle for keeping a vehicle at rest, the brake member is actuated with the actuation system to dispose the brake member in the braking configuration in a parking state in which the brake member prevents rotation of the wheel and the brake member disposed in the parking state is engaged with a parking lock to thereby prevent the brake member from moving out of the parking state. The actuation member is allowed to stop actuating the brake member while the brake member disposed in the parking state is engaged by the parking lock. [0032] In accordance with another aspect, there is provided a braking system for a vehicle comprising a wheel. The braking system includes a braking operator configured to be operated by a driver of the vehicle for requesting slowing of the vehicle and a vehicle immobilization operator configured to be operated by the driver for requesting immobilization of the vehicle. A brake assembly is operatively connected to the wheel and includes a brake member moveable between a non- braking configuration and a braking configuration in which the brake member engages the wheel. The brake assembly is disposable in one of a slowing state in which the brake member engages the wheel so as to slow rotation thereof, and a parking state in which the brake member engages the wheel so as to prevent rotation thereof. An actuation system is operatively connected to the braking operator and the vehicle immobilization operator. The actuation system has an actuation member operatively connected to the brake member and configured to apply a force on the brake member to move the brake member between the non-braking configuration and the braking configuration, and to selectively dispose the brake member in the one of slowing state and the parking state. A parking lock is operatively connected to the vehicle immobilization operator. The parking lock is configured to selectively engage the brake member and to thereby prevent the brake member from moving out of the parking state if the brake member is engaged by the parking lock when disposed in a parking state. A maximum force exertable by the parking lock on the brake member is incapable of changing configuration of the brake member from the non-braking configuration to the parking state.

[0033] In some implementations, the parking lock is configured to engage the brake member when the brake member is disposed in the parking state. [0034] In some implementations, the parking lock is self-locking.

[0035] In some implementations, the parking lock includes an output shaft, an input shaft and a parking lock motor. The output shaft is configured to engage the actuation member. The input shaft engages the output shaft which is moveable with respect to the input shaft. The input shaft is operatively connected to the parking lock motor for driving the output shaft. The output shaft is driven by the input shaft between a disengaged position and an engaged position in which the output shaft engages the brake member with the brake member being disposed in the parking state and thereby prevents the brake member from moving out of the parking state. The output shaft is self-locking with respect to a force applied by the brake member on the output shaft.

[0036] In some implementations, the brake member is actuated along a brake actuation axis. The input shaft and the output shaft are disposed one of parallel to and coaxial with the brake actuation axis. The output shaft is driven along a parking lock actuation axis, the parking lock actuation axis is parallel to or coaxial with the brake actuation axis.

[0037] In some implementations, the actuation member is a piston and the actuation system is a hydraulic actuation system. The hydraulic actuation system further includes a hydraulic cylinder. The piston is disposed within the hydraulic cylinder. A central axis of the piston is disposed one of coaxial with and parallel to the input shaft and the output shaft.

[0038] In some implementations, the piston includes a first end contacting the brake member, and a second end opposite the first end and disposed inside the hydraulic cylinder. A bore extends from the second end towards the first end. At least a portion of the output shaft is disposed in the bore and selectively engaging the piston when the brake member is disposed in the parking state to prevent the brake member from moving out of the parking state. [0039] In some implementations, the brake member is at least one brake pad and the brake assembly is a disc brake assembly. The disc brake assembly further includes a rotor mounted to the wheel to be rotatable with the wheel, and a caliper being rotationally fixed and defining the hydraulic cylinder. The at least one brake pad is mounted to the caliper and selectively engages the rotor for braking the wheel. The at least one brake pad is operatively connected to the actuation member and the parking lock.

[0040] In some implementations, the parking lock motor is mounted to the brake assembly. [0041] In some implementations, the actuation member is a piston and the actuation system is a hydraulic actuation system comprising a hydraulic cylinder, the piston being disposed within the hydraulic cylinder.

[0042] In some implementations, the brake member is at least one brake pad and the brake assembly is a disc brake assembly. The disc brake assembly further includes a rotor mounted to the wheel to be rotatable with the wheel and a caliper being rotationally fixed. The at least one brake pad is mounted to the caliper and selectively engages the rotor for braking the wheel, the at least one brake pad being operatively connected to the actuation member and the parking lock. [0043] In accordance with another aspect, there is provided a braking system for a vehicle comprising a wheel. The braking system includes a brake member operatively connected to the wheel of the vehicle. An actuation system is operatively connected to the brake member and configured to actuate the brake member by applying a force thereto. The actuation system is configured to actuate the brake member responsive to receiving a request for slowing the vehicle to dispose the brake member in a braking configuration in a slowing state in which the brake member slows rotation of the wheel. The actuation system is further configured to actuate the brake member responsive to receiving a request for immobilizing the vehicle to dispose the brake member in the braking configuration in a parking state in which the brake member prevents rotation of the wheel. A parking lock is configured to engage the brake member disposed in the parking state to thereby prevent the brake member from changing out of the parking state.

[0044] For the purpose of this application, terms related to spatial orientation such as downwardly, rearward, forward, front, rear, left, right, above and below are as they would normally be understood by a driver of the vehicle sitting thereon in an upright position with the vehicle in a straight ahead orientation (i.e. not steered left or right), and in an upright position (i.e. not tilted).

[0045] Implementations of the present technology each have at least one of the above-mentioned object and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein.

[0046] Additional and/or alternative features, aspects, and advantages of implementations of the present technology will become apparent from the following description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where: [0048] FIG. 1 is a left side elevation view of a prior art three-wheel vehicle;

[0049] FIG. 2 is a perspective view of a prior art braking system for the vehicle of FIG. 1 ;

[0050] FIG. 3 is a schematic cross-sectional view of a brake assembly and a parking lock of a braking system in accordance with an implementation of the present technology;

[0051] FIG. 4 is a schematic cross-sectional view of a brake assembly and a parking lock in accordance with another implementation of the present technology;

[0052] FIG. 5 is a schematic illustration of a braking system having the brake assembly and parking lock of FIG. 3 or 4; [0053] FIG. 6 is a flowchart illustrating a method of braking, in accordance with an implementation of the present technology, using the braking system of FIG. 5.

DETAILED DESCRIPTION

[0054] A braking system 300 described below is implemented in the three- wheel saddle-seat vehicle 10 discussed above in place of the braking system 80 discussed above. The braking system 300 and a method 400 for braking the rear wheel 16 of the vehicle 10 in accordance with an implementation of the present technology will now be described with reference to FIGs. 3 to 6. [0055] Although the present technology is being described with respect to a three-wheel straddle-type vehicle 10, it is contemplated that the present technology could be used on other types of vehicles such as, for example, three- or four-wheel all- terrain vehicles. [0056] The braking system 300 includes some features that are similar to those of the braking system 80 discussed above. The braking system 300 includes a regular brake operator 60 in the form of the brake pedal 60 and the parking brake operator 62 (referred to hereinafter as the vehicle immobilization operator 62) in the form of a button similar to that of the braking system 80 described above. It is contemplated that the regular brake operator 60 could be in the form of a hand-operated brake lever connected to the handlebars 52 instead of the foot-operated brake lever shown herein. It is also contemplated that the vehicle could have both of the hand-operated and foot- operated forms of regular brake operator 60. It is contemplated that the vehicle immobilization operator 62 could be in the form of a knob or a lever that is moveable between two positions for engaging or disengaging the parking brake. It is contemplated that the vehicle immobilization operator 62 could be located elsewhere on the vehicle than on the handlebars 52 as shown herein. In some implementations, the braking system 300 could also includes the start-up operator 56 in the form of a button/key for starting and stopping operation of the vehicle 10 as discussed above. [0057] The braking system 300 includes brake assemblies 82 connected to each of the front wheels 14 that are similar to the brake assembly 82 of the front wheels 14 as described above. The front wheel brake assemblies 82 will not be described again herein in detail. It is contemplated that the brake assemblies 82 connected to the front wheels 14 could be omitted. [0058] The braking system 300 includes a brake assembly 310 connected to the rear wheel 16 which is described below. The brake assembly 310 is a disc-type brake assembly having some features that are similar to the brake assembly 82 of FIGs. 1 and 2 discussed above. The brake assembly 310 has a rotor 312 that is configured to be mounted on to the hub of a wheel (not shown) similar to the wheels 14, 16 and a caliper 314 straddling the rotor 312. The caliper 314 is mounted to the swing arm 22 of the rear suspension assembly 20. The wheel 16 and the rotor 312 rotate about a rotational axis 315. A pair of brake pads 316 mounted to the caliper 314 are disposed on either side of the rotor 312. The brake pads 316 are actuated (as will be described below in further detail) by a piston 318 to squeeze the rotor 312 from either side to cause braking of the wheel (not shown) connected to the rotor 312.

[0059] The caliper 314 is a floating caliper that is slidably mounted on a caliper bracket (not shown) such that it has a limited amount of translational movement with respect to the rotor 312 in a direction parallel to the rotational axis 315. On one side of the rotor 312, the caliper 314 defines a cylinder 320. The piston 318 is disposed in the cylinder 320 and is movable along a piston actuation axis 321 disposed parallel to the rotational axis 315. One end 322 of the piston 318 abuts the right brake pad 316 (as viewed in Fig. 3) and actuates the right brake pad 316 leftwardly along a brake actuation axis 323, also disposed parallel to the piston actuation axis 321 and the rotational axis 315. A second end 324 of the piston 318 opposite the first end 322 is disposed inside the cylinder 320. A central bore 326 extends into the piston 318 from the second end 324. The central bore 326 houses a parking lock 330 that will be described below in further detail. The central bore 326 is formed coaxially with the cylinder 320 and the piston actuation axis 321. The caliper 314 also defines a brake fluid opening 328 that serves as an inlet and outlet for delivering and removing brake fluid to and from the cylinder 320. The cylinder 320 is filled with brake fluid for actuating the piston 318, and thereby the brake pads 316. The brake fluid flowing into the cylinder 320 pushes the piston 318 leftwardly along the piston actuation axis 321, thereby pushing the right brake pad 316 against the right side surface of the rotor 312. The brake fluid flowing into the cylinder 320 also causes the caliper 314 to slide rightwardly along the bracket (not shown), thereby pushing the left brake pad 316 against the left side surface of the rotor 312. Once the brake pads 316 contact the rotor 312, no additional brake fluid can flow into the cylinder 320 but the hydraulic pressure of the brake fluid can be increased as discussed below to increase friction between the brake pads 316 and the rotor 312 for slowing/immobilization of the vehicle 10. It is contemplated that more than one piston 318 could be provided adjacent one of the two brake pads 316. It is further contemplated that the caliper 314 could be a fixed caliper with at least one piston 318 on each side of the rotor 312, with each of the at least one pistons 318 actuating a corresponding one of the pair of brake pads 316. [0060] The braking system 300 includes a hydraulic actuation system 350

(shown schematically in Fig. 5) similar to the hydraulic actuation system 100 for actuating the brake pads 316 via the piston 318. The hydraulic actuation system 350 includes the piston 318, a master cylinder 354 and a fluid reservoir 355 connected thereto. The master cylinder 354 is selectively fluidly connected to each brake assembly 82, 310 via a manifold 356 and valves 357 of the hydraulic actuation system 350. Each valve 357 controls flow of brake fluid and distribution of brake pressure to a corresponding one of the brake assemblies 82, 310 via a corresponding brake line 352. Similar to the master cylinder 102 described above, the master cylinder 354 is also fluidly connected to the brake pedal 60 such that when the brake pedal 60 is actuated by the driver of the vehicle 10, brake fluid is pushed out of the master cylinder 354 via the manifold 356 and the valves 357 towards one or more of the corresponding brake assembly 82, 310. A braking control unit 360 is connected to the valves 357 to control how the hydraulic pressure created by the master cylinder 354 is distributed between the brake assemblies 82, 310 in order to slow down and maintain stability of the vehicle 10. The hydraulic system 350 also includes a hydraulic pump 358 that can pump brake fluid to each of the brake assemblies 82, 82, 310 via the manifold 356 and valves 357 independently of, or in addition to, the master cylinder 354. The braking control unit 360 is connected to the hydraulic pump 358 to control the operation of the hydraulic pump 358 and thereby to control distribution of brake fluid (and hydraulic pressure) to each brake assembly 82, 310. The manifold 356, valves 357 and the hydraulic pump 358 form an electronically controlled hydraulic unit 351 of the hydraulic actuation system 350 that can be controlled by the braking control unit 360 independently of the master cylinder 354 which is controlled by the brake pedal 60. It is contemplated that the hydraulic pump 358 could be omitted, and that the brake assemblies 82, 310 could only be actuated via the master cylinder 354. The braking control unit 360 is also in communication with the vehicle immobilization operator 62 and a parking lock motor 336 for using the hydraulic actuation system 350 to actuate the brake pads 316 when the driver presses the parking brake button 62 as will be described below. It is contemplated that the braking control unit 360 could be provided as a plurality of separate modules for controlling different functions, and/or some of the modules of the braking control unit 360 could be integrated with the ECU 30. [0061] With reference again to Fig. 3, the opening 328 of the caliper 314 is connected to a corresponding brake line 352 of the hydraulic actuation system 350 for actuation of the brake pads 316, and corresponding slowing/immobilization of the vehicle 10. [0062] When the brake pedal 60 is actuated by the driver to slow the vehicle

10, the brake pads 316 are actuated by the hydraulic system 350 via the master cylinder 354. When the brake pedal 60 is actuated, at first, brake fluid is pushed out of the master cylinder 354 causing brake fluid further downstream in the brake line 352 of the hydraulic system 350 to flow into the cylinder 320, thereby moving the piston 318 and the caliper 314 so as to increase the volume of the cylinder 320 and to push the brake pads 316 towards the rotor 312. Once the brake pads 316 have come into contact with the rotor 312, the piston 318 and the caliper 314 cannot move any further and the volume of the cylinder 320 cannot increase any further. Further actuation of the brake pedal 60 after the brake pads 316 are in contact with the rotor 312 results in increasing hydraulic pressure on the piston 318 and caliper 314, which in turn exerts an increasing force on the respective brake pad 316 resulting in increased friction between the brake pads 316 and the rotor 312. The hydraulic pressure and therefore the friction between the brake pads 316 and the rotor 312 can be controlled by actuating the brake pedal 60 more or less. Since the rotational speed of the rotor 312, and the wheel 16 connected thereto, reduces by an amount depending on the magnitude of friction between the brake pads 316 and the rotor 312, the desired reduction of vehicle speed can thus be achieved by controlling the actuation of the brake pedal 60.

[0063] When the driver stops actuating the brake pedal 60, the hydraulic pressure on the piston 318 and caliper 314 is released, thereby reducing force exerted on the brake pads 316 and reducing friction between the brake pads 316 and the rotor 312. The force exerted by the hydraulic system 350 on the brake pads 316 gradually decreases as the brake fluid drains out of the cylinder 320 into the manifold 356 and the brake pads 316 eventually disengage from the rotor 312 and return to their original position.

[0064] When the vehicle immobilization operator 62 is operated to by the driver to request immobilization of the vehicle 10 (sometimes referred to colloquially as "requesting parking brake" or "requesting engagement of parking brake"), the brake pads 316 are actuated by the hydraulic system 350 via the hydraulic pump 358.. In response to the vehicle immobilization operator 62 being pressed, the braking control unit 360 operates the hydraulic pump 358 which pushes brake fluid towards the cylinder 320. Operation of the hydraulic pump 358 at first causes brake fluid to flow into the cylinder 320 from the brake line 352 and the brake pads 316 to move into contact with the rotor 312. Once the brake pads 316 are in contact with the rotor 312, no additional brake fluid can flow into the cylinder 320 as described above. Further operation of the hydraulic pump results in increasing the hydraulic pressure in the cylinder 320. In the illustrated implementation, when the vehicle immobilization operator 62 is pressed by the driver and once the brake pads 316 are contacting the rotor 312, the hydraulic pump 360 is controlled by the braking control unit 360 to create sufficient hydraulic pressure to exert sufficient force on the brake pads 316 so as to have sufficient friction between the brake pads and the rotor 312 to prevent the rotor 312 from rotating in the absence of the wheel 16 being driven by the engine 30. In the illustrated implementation, the pressing of the vehicle immobilization operator 62 also causes the braking control unit 360 to engage the brake pads 316 with the parking lock 330 and stop operation the pump 358 so as to release the hydraulic pressure in the cylinder 320, as will be described below to immobilize the vehicle 10. [0065] When the vehicle immobilization operator 62 is operated again by the driver to remove the request for immobilization of the vehicle 10 (sometimes referred to colloquially as "requesting disengagement of parking brake"), the parking lock 330 is disengaged from the brake pads 316 to allow the brake pads 316 to disengage from the rotor 312 and return to their original position. [0066] The brake assembly 310 is in a non-braking configuration when the brake pads 316 are not in contact with the rotor 312. Therefore, in the non-braking configuration, there is no friction between the brake pads 316 and the rotor 312, and the rotation of the rotor 312, and thereby of the wheel 16, is thus not hampered by the brake pads 316. [0067] When the brake pads 316 are in contact with the rotor 312, the brake assembly 310 is in a braking configuration as shown in Fig. 3. In the braking configuration, the brake pads 316 can be in a slowing state or a parking state as described below.

[0068] The slowing state is defined to be one in which the brake pads 316 push against the rotor 312 such that the friction therebetween is sufficient to slow rotation of the rotor 312, and thereby the wheel 16 connected to the rotor 312. Any force applied by hydraulic actuation system 350 on the brake pads 316 to actuate the brake pads 316 such that the brake pads 316 are moved from the non-braking configuration to the braking configuration and then disposed in a slowing state pushing against the rotor 312 such that the friction therebetween is sufficient to slow rotation of the rotor 312 is referred to herein as a slowing force. Typically, the brake pad 316 is in the slowing state as a result of the brake pedal 60 being actuated by the driver of the vehicle 10 to reduce the vehicle speed while the vehicle 10 is moving. The driver can of course also actuate the brake pedal 60 to apply a force to the brake pads 316 while the vehicle 10 is stationary, preventing the rotation of the wheels 16. The braking system 300 enables the driver to apply a wide range of slowing forces which can be varied by the driver to alter the rate of deceleration of the vehicle 10.

[0069] The parking state is defined to be one in which the brake pads 316 push against the rotor 312 such that the friction therebetween is sufficient to prevent the rotor 312 and thereby the wheel 16 connected thereto from beginning rotation (in the absence of the wheel 16 being driven by the engine 30 to turn). The force exerted by the hydraulic actuation system 350 on the brake pads 316 to actuate the brake pads 316 such that the brake pads 316 are moved from the non-braking configuration to the braking configuration and then disposed in a parking state pushing against the rotor 312 such that the friction therebetween is sufficient to prevent rotation of the rotor 312 in the absence of the wheel 16 being driven by the engine 30 to turn is referred to herein as a parking force. In the present implementation, the braking control unit 360 causes generation of substantially the same parking force on the brake pads 316 whenever the driver requests immobilization of the vehicle 10. This parking force falls within the range of slowing forces generated for slowing the vehicle 10. [0070] In the illustrated implementation, the physical positions of the rotor, the caliper 314, the brake pads 316 and the piston 318 relative to one another is the same in the parking state and in the slowing state. The slowing state and the parking state are defined with respect to the friction between the brake pads 316 and the rotor 312 in each state. It is however contemplated that the brake assembly 310 could be configured differently than as shown herein such that the physical positions of the caliper 314, the brake pads 316 and the piston 318 relative to one another could be different in the parking state compared to the slowing state of the braking configuration.

[0071] With reference still to Fig. 3, the braking system 300 also includes the parking lock 330 disposed in the central bore 326 of the piston 318. The parking lock 330 comprises an input shaft 332, an output shaft 334 and the parking lock motor 336. The parking lock motor 336 is disposed outside the cylinder 320. In the illustrated implementation, the parking lock motor 336 is mounted to the caliper 314. It is contemplated that the parking lock motor 336 could not be mounted to the caliper 314. One end of the input shaft 332 is connected to the parking lock motor 336 and extends through an opening 338 defined in the body of the caliper 314 into the cylinder 320. Inside the cylinder 320, the input shaft 332 extends into the central bore 326 of the piston 318. The opening 338 of the caliper 314 is coaxial with the bore 326. The parking lock motor 336 rotates the input shaft 332 about a central axis of the input shaft 332. The input shaft 332 can be rotated in a clock-wise or anticlockwise direction. The portion of the input shaft 332 disposed inside the cylinder 320 is externally threaded and engaged by an internally threaded bore of the output shaft 334 which is also disposed in the central bore 326 of the piston 318. One end 340 of the output shaft 334 is disposed in the piston bore 326 and selectively abuts the inner surface of the piston 318 at the end 322. The opposite end 342 of the output shaft 334 is disposed outside the piston bore 326. It is contemplated that the end 342 could also be disposed inside the piston bore 326. A rotation of the input shaft 332 in one of a clock-wise or anti-clockwise direction advances the output shaft 334 along the input shaft 332 while a rotation of the input shaft 332 in the other of the clockwise or anti-clockwise direction retracts the output shaft 334 along the input shaft 332. Since the input shaft 332 is axially fixed in position relative to the caliper 314, the rotation of the input shaft 332 results in an axial translation of the output shaft 334 along a lock actuation axis 331 coaxial with the central axis of the input shaft 332. The lock actuation axis 331 is also coaxial with the piston actuation axis 321. [0072] When the end 340 of the output shaft 334 abuts the inner surface of the piston 318, the piston 318 is prevented from being retracted into the cylinder 320 and the caliper 314 is prevented from translating with respect to the rotor 312. Consequently, the left and right brake pads 316 are prevented from moving away from the rotor 312, leftwardly and rightwardly respectively. The brake pads 316 are thus engaged and locked by the parking lock 330. When the brake pads 316 are locked by the parking lock 330 while being disposed in a parking state, the vehicle 10 is considered to be immobilized.

[0073] In the illustrated implementation, the parking lock 330 engages the right brake pad 316 via the piston 318. It is however contemplated that the parking lock 330 could be configured to engage one or both of the brake pads 316 independently of the piston 318. Thus, the parking lock 330 could be in direct contact with the brake pad 316 (as seen in the implementation of the parking lock 330' of FIG. 4), or contacting the brake pad 330 via another element other than the piston 318.

[0074] The parking lock 330 is configured such that a maximum force exertable by the parking lock 330 on the right brake pad 316 as a result of the electric motor 336 driving the input shaft 332 is less than the force needed to move the brake pads 316 from the non-braking configuration to parking state. Thus, the brake pads 316 are actuated by the hydraulic actuation system 350 to be disposed in the braking configuration in the parking state, and then locked in the parking state by the parking lock motor 336 driving the input shaft 332. The parking lock motor 336 is operatively connected to the braking control unit 360 for controlling the parking lock motor 336 to drive the input shaft 332 when the user presses the vehicle immobilization operator 62.

[0075] In contrast to the prior art braking system 80 described above, in the braking system 300, the hydraulic actuation system 350 actuates the brake pads 318 both for disposing the brake pads 316 in the slowing state (for slowing the vehicle 10) and for disposing the brake pads 316 in the parking state (for preventing the vehicle 10 from moving while it is parked). Since the parking lock motor 336 is not used to actuate the brake pads 316 to dispose the brake pads 316 in a parking state (i.e. to exert the parking force on the brake pads 316), the parking lock motor 336 of the braking assembly 300 is less powerful, and consequently, smaller in size than the electric motor in the braking system 80 which is used to actuate the brake pads via the parking brake actuator arm 92. The smaller size of the parking lock motor 336 facilitates and simplifies integration of the parking lock motor 336 with the caliper 314 as shown herein, instead of requiring mounting of the parking lock motor 336 remotely from the wheel 16 as the electric motor of the braking system 80. It is contemplated however that the parking lock motor 336 could be mounted other than on the caliper 314 and/or remotely from the wheel 16. It is also contemplated that the parking lock motor 336 could not be less powerful and/or smaller in size than the electric motor of the prior art braking system 80.

[0076] The parking lock 330 is self-locking in that when power to the parking lock motor 336 is removed, the internal friction between the input and output shafts 332 and 334 is sufficient to prevent any force exerted on the output shaft 334 via or from the piston 318, the brake pads 316 or the rotor 312 from pushing the output shaft 334 in a direction away from the brake pad 316, an effect known as back-driving. Thus, the output shaft 334 can be driven by the electric motor 336 via the input shaft 332 but the output shaft 334 cannot be driven by the brake pads 316. It will be appreciated that the parking lock 330 need only be self-locking within the range of operating conditions to which the vehicle will be subjected. [0077] It is contemplated that the parking lock 330 could be configured differently than as shown herein. It is contemplated that the input shaft 332 and the output shaft 334 could be disposed other than parallel to the piston actuation axis 321 and the brake actuation axis 323. It is contemplated that the parking lock 330 could be a blocking mechanism without being self-locking with respect to a force exerted on the parking lock 330 by the brake pads 316.

[0078] FIG. 4 shows a portion of a braking system 300' that is an alternative to the braking system 300 described above. The braking system 300' has many features that are similar to the features of the braking system 300 described above. As such similar and corresponding features of the braking system 300 and 300' have been labeled with the same reference numbers and will not be discussed again herein. [0079] The braking system 300' has a brake assembly 310' and a parking lock

330' that is disposed outside the hydraulic cylinder 320. As such, the piston 318' of the brake assembly 310' does not have the central bore 326 that is included in the piston 318 described above. The parking lock 330' includes a parking lock member 332' that selectively abuts a right side surface of the right brake pad 316 when the right brake pad 316 is disposed in the parking state, thereby blocking the right brake pad 316 from moving rightwardly out of the parking state. The parking lock 330' is actuated by a parking lock motor (not shown) along an actuation axis 331 '. The actuation axis 331 ' is perpendicular to the piston actuation axis 321, the brake member actuation axis 323. In this configuration of the parking lock 330', the parking lock 330' is not self-locking but locks the brake pads 316 in the parking state by blocking the brake pads 316.

[0080] The braking control unit 360 controls the operation of the hydraulic actuation system 350 and the parking lock motor 336 for placing the brake assembly in a desired configuration and desired state as will be described below with reference to FIG. 5. The braking system 300, 300' is provided with various sensors (not shown) that are operatively connected to the braking control unit 360 to enable the braking control unit 360 to monitor the configuration and state of the brake assembly 310, 310' and accordingly actuate the brake pads 316 and/or engage the brake pads 316 with the parking lock 330, 330'. The sensors could include pressure sensors for sensing the hydraulic pressure of brake fluid in the hydraulic actuation system 350, position sensors for sensing the position of a component such as the brake pads 316, the caliper 314, the piston 318 and the like.

[0081] In the illustrated implementation, the parking lock 330, 330', is connected to the brake assembly 310, 310' mounted to the rear wheel 16. It is contemplated however that one or both of the front wheels 14 could have the brake assembly 310, 310' and the parking lock 330, 330', instead of, or in addition to the rear wheel 16.

[0082] The method 400 for braking in a braking system 300, 300' will now be described with reference to FIG. 6. [0083] At step 420, the braking control unit 360 waits for a request for braking the vehicle 10 for slowing the vehicle 10. In the illustrated implementation, the request for braking the vehicle 10 for slowing the vehicle 10 is made by the driver of the vehicle 10 by operating the brake pedal 60. It is contemplated that the request could also be made by the electronic brake control unit 360 based on a particular operating condition of the vehicle 10, for example, an instability, a locking of the wheels 14, 16 and the like. Upon receiving the request for braking the vehicle 10 for slowing the vehicle 10, the method 400 proceeds to step 425 to actuate the brake pads 316. If a request for braking the vehicle 10 for slowing the vehicle 10 has not occurred, the method 400 proceeds to step 440.

[0084] At step 425, the brake pads 316 are actuated by causing the hydraulic actuation system 350 to apply a slowing force on the brake pads 316 to dispose the brake pads 316 (and the braking assembly 310) in a slowing state for slowing the vehicle 10. In the illustrated implementation, actuation of the brake pedal 60 by the driver (request for slowing the vehicle 10) directly results in a hydraulic force being applied on the brake pads 316, i.e. the driver of the vehicle 10 causes the hydraulic actuation system 350 to apply the slowing force. The braking control unit 360 controls the hydraulic actuation system 350 to regulate the slowing force on the brake pads 316 in response to an actuation of the brake pedal 60 by the driver. The braking control unit 360 can also cause the hydraulic pump 358 to exert the slowing force on the brake pads 316 independently of the brake pedal 60 being pressed.

[0085] After the brake pads 316 are actuated at step 420, at step 430, the braking control unit 360 determines if the braking request has ended. The braking request is determined to have ended when the condition that caused the braking request at step 420 ends. Thus, for example, if the driver stops pressing the brake pedal 60, or the vehicle operating condition such as instability is no longer present, the braking request is determined to have ended. If the braking request is determined to not have ended at step 430, the braking control unit 360 returns to step 425 to continue actuation of the brake pads 316 with the hydraulic actuation system 350. [0086] If at step 430, the braking request is determined to have ended, the hydraulic system 350 is caused to stop actuating the brake pads 316 at step 435. The slowing force being exerted on the brake pads 316 is removed so that the rotor 412 can rotate freely. In the illustrated implementation, where the pressing of the brake pedal 60 directly results in the slowing force being exerted on the brake pads 316, releasing the brake pedal 60 causes the hydraulic actuation system 350 to reduce the hydraulic pressure in the cylinder 320. The slowing force then gradually decreases as the brake fluid drains out of the cylinder 320 into the manifold 356. Alternately, the braking control unit 360 controls the hydraulic pump 358 to stop pumping brake fluid into the cylinder 320, resulting in the decrease and eventual reduction of slowing force on the brake pads 316.

[0087] If a request for braking the vehicle 10 for slowing the vehicle 10 has not occurred at step 420, the method 400 proceeds to step 440.

[0088] At step 440, the braking control unit 360 waits for a parking brake request (i.e. a request for immobilization of the vehicle 10) for keeping a vehicle 10 at rest. In the illustrated implementation, the parking brake request is made by the driver of the vehicle 10 by operating the vehicle immobilization operator 62. It is contemplated that the parking brake request could also be made by the electronic brake control unit 360 based on a particular operating condition of the vehicle 10. For example, the vehicle 10 could be configured to automatically engage the parking lock 330, when the engine 30 is turned off (via operation of the start-up operator 56 for example), or when the transmission (not shown) is disposed in a transmission parking configuration. Upon receiving the parking brake request for keeping a vehicle 10 at rest, the method 400 proceeds to steps 450 to 470 to engage the parking lock 330. If a parking brake request for keeping a vehicle 10 at rest has not occurred, the method 400 returns to step 420.

[0089] Although the steps 420 and 440 have been described herein as distinct steps of the method 400, it should be understood that the steps 420 and 440 could occur in reverse order than as described herein, or simultaneously. In a sense, both of the steps 420 and 440 are always being performed in the vehicle 10.

[0090] At step 450, the brake pads 316 are actuated by the hydraulic actuation system 350 by causing the hydraulic actuation system 350 to apply a parking force on the brake pads 316 to dispose the brake pads 316 (and brake assembly 310) in a parking state in which the brake pads 316 push against the rotor 312 to prevent rotation of the wheel 16 that the rotor 312 is mounted to.

[0091] In the illustrated implementation, the hydraulic pump 358 is caused by the braking control unit 360 to actuate the brake pads 316 responsive to the vehicle immobilization operator 62 being pressed by the driver of the vehicle 10. When the vehicle immobilization operator 62 is pressed by the driver, and if the parking lock 330 is not currently engaged, the braking control unit 360 controls the hydraulic pump 358 of the hydraulic actuation system 350 as described above to actuate the brake pads 316. In alternative implementations, the driver causes the master cylinder 354 of the hydraulic actuation system 350 to actuate the brake pads 316 to place the brake pads 316 in the parking state by pressing on the brake pedal 60. The driver could press the brake pedal 60 to actuate the brake pads 316 while pressing the vehicle immobilization operator 60, before pressing the vehicle immobilization operator 62, or after pressing the vehicle immobilization operator 62 to operate the parking lock 330 for engaging the brake pads 316.

[0092] At step 460, the parking lock motor 336 is operated to engage and lock the brake pads 316 in the parking state. With the right brake pads 316 disposed in the parking state, the input shaft 332 is driven by the parking lock motor 336 to extend the output shaft 334 until it abuts the piston 340 so that the brake pads 316 are engaged with the parking lock 330 and thereby prevented from moving out of the parking state.

[0093] In the illustrated implementation, operation of the parking lock motor

336 to engage the brake pads 316 is started after the brake pads 316 have been actuated by the hydraulic actuation system 350 to be disposed in the parking state (step 450) and while the hydraulic actuation system 350 is applying the parking force on the brake pads 316 to keep the brake pads 316 disposed in the parking state. Thus, step 460 is implemented after step 450 has been completed.

[0094] The braking control unit 360 could control the operation of the hydraulic actuation system 350 and the parking lock motor 336 based on information received from various sensors (pressure sensors, position sensors, vehicle speed sensors, and the like) which enable the braking control unit 360 to monitor the configuration of the braking assembly 300 in real time. In some implementations, the braking control unit 360 may control the operation of the hydraulic actuation system 350 and the parking lock motor 336 based on appropriate predefined time delays between the beginning of the implementation of steps 450 and 460.

[0095] It is also contemplated that steps 450 and 460 could be performed simultaneously, or that step 460 could begin after step 450 has begun but before step 450 has been completed. In such an implementation, the parking lock motor 336 is operated (step 460) to extend the output shaft 334 before the brake pads 330 have been placed in the parking state (step 450). The parking lock motor 336 could begin driving the output shaft 334 at the same time as the hydraulic actuation system 350 begins increasing the hydraulic pressure in the cylinder 320 to actuate the brake pads 316 to place the brake pads 316 in the parking state, or shortly thereafter.

[0096] In the illustrated implementation, the parking lock motor 336 is operatively connected to the vehicle immobilization operator 62 via the braking control unit 360 such that the braking control unit 360 controls the parking lock motor 336 responsive to receiving the parking brake request from the vehicle immobilization operator 62 to drive the input shaft 332, and thereby the output shaft 334 to engage the brake pads 316. It is contemplated that the parking lock motor 336 could be operatively connected to the vehicle immobilization operator 62 directly so that the parking lock motor 336 could be controlled directly by the driver by pressing the vehicle immobilization operator 62. It is also contemplated that the operation of the parking lock motor 336 for engaging the brake pads 316 could be prevented in certain conditions, such as, for example, if the vehicle speed is greater than a predefined threshold speed.

[0097] At step 470, the actuation system 350 removes the parking force applied on the brake pads 316 while the brake pads 316 are disposed in the parking state and engaged by the parking lock 330. Once the braking control unit 360 determines that the brake pads 316 are engaged by the parking lock 330, the braking control unit 360 causes the hydraulic actuation system 350 to allow release of the hydraulic pressure in the cylinder 320 and retraction of the piston 318, thereby removing the parking force on the brake pads 316. [0098] As discussed above in connection with stopping actuation of the brake pads 316 by the hydraulic actuation system 350 after slowing the vehicle 10, removing the parking force on the brake pads 316 implies stopping actively pushing brake fluid towards the cylinder 320 so that the hydraulic pressure of brake fluid in the cylinder 320 and the force exerted thereby on the brake pads 316 gradually decreases over time as the brake fluid gradually drains out of the cylinder 320 into the manifold 356.

[0099] In some implementations, the parking force is removed as soon as the parking lock 330 engages the brake pad 318 even if the engine 30 remains on. [00100] In some implementations, the hydraulic actuation system 350 continues to apply the parking force on the brake pads 316 until the driver requests an end to operation of the vehicle 10 using the start-up operator 56. Thus, if the parking lock 330 is engaged while the vehicle 10 is operating (engine 30 is on), the hydraulic actuation system 350 continues to exert the parking force on the brake pads 316 while the parking lock 330 engages the brake pads 316. In this implementation, the parking force exerted on the brake pads 316 is removed only when the engine 30 is turned off.

[00101] When the brake pads 316 are engaged by the parking lock 330, the driver can request disengagement of the parking brake (i.e. request an end to immobilization of the vehicle 10) by pressing the vehicle immobilization operator 62 again. As mentioned above, it is also contemplated that the parking brake operator 62 could be in the form of a switch (physical or electronic) or a knob that can be moveable between having two positions, one corresponding to requesting parking brake engagement and the other to requesting parking brake disengagement. The steps for disengaging the parking lock 330 will now be described proceeding onwards from step 470.

[00102] At step 480, the braking control unit 360 waits for a request for disengaging the parking brake (i.e. a request for ending immobilization of the vehicle 10).

[00103] When a request for disengaging the parking brake is received at step 480, the method 400 proceeds to step 490 where the parking lock 330 is disengaged from the brake pads 316 by causing the parking lock motor 336 to drive the input shaft 332 in the appropriate direction. In the illustrated implementation, the parking lock motor 336 is controlled by the braking control unit 360 which thus causes the parking lock motor 336 to drive the input shaft 332 in the appropriate direction for disengaging form the brake pads 316. It is contemplated that the parking lock motor 336 could be configured such that the operation of the parking lock motor 336 (and the direction in which the input shaft 332 is driven) can be controlled directly by the driver by via the parking brake operator 62.

[00104] In some implementations, before causing the parking lock motor 336 to disengage the parking lock 330 from the brake pads 316, the braking control unit 360 causes the hydraulic actuation system 350 to reapply the parking force on the brake pad 316 which would enable the brake pads 316 to be disposed in the parking state in the absence of the parking lock 330 engaging the brake pads 316. Then, once the parking force is reapplied on the brake pads 318, the braking control unit 360 causes the parking lock 330 to be disengaged (by causing the parking lock motor 336 to drive the input shaft 332 in the appropriate direction) from the brake pads 318 while the hydraulic actuation system 350 continues to apply the parking force on the brake pads 318. After disengaging the parking lock 330 from the brake pads 318, the braking control unit 360 causes the actuation system 350 to remove the parking force applied on the brake pads 318 to allow the braking pads 318 to be removed from the parking state. In some implementations, the parking force is gradually reduced to prevent any abrupt changes in the configuration of the brake pads 316.

[00105] Although the braking system 300, 300' and method 400 has been described above with respect to a disc-type brake assembly 310, 310', it should be understood that the method 400 and the system 300, 310 could also be implemented with a drum-type brake assembly having a brake drum instead of a rotor 312, and a pair of brake shoes instead of the brake pads 316 which can be actuated by a pair of pistons to squeeze the brake shoes against the brake drum for braking a wheel operatively connected to the brake drum. Therefore, the rotor 312 and the drum can be referred to generally as a rotating member 312, and the brake pads 316 or brake shoes can be referred to more generally as the brake member 316.

[00106] Furthermore, the braking system 300, 300' and method 400 is being described herein with respect to a hydraulic actuation system 320 including the hydraulic piston 318, 318' for actuating the brake member 316. It should be understood however that the actuation system for actuating the brake member 316 could be an actuation system other than hydraulic, such as a pneumatic actuation system, and the like. The hydraulic actuation system 350 and the hydraulic piston 318 can therefore be referred to generally as actuation system 320 and actuation member 318 respectively.

[00107] Modifications and improvements to the above-described implementations of the present vehicle may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present technology is therefore intended to be limited solely by the scope of the appended claims.

Claims

is claimed is:

A method of braking a vehicle,

the vehicle comprising:

a brake member operatively connected to a wheel of the vehicle; and an actuation system operatively connected to the brake member and configured to apply a force thereto, the brake member being actuated when the actuation system applies the force thereto,

the actuation system being configured to actuate the brake member to dispose the brake member in a braking configuration in a slowing state for braking of the wheel responsive to receiving a request for slowing the vehicle, the method comprising:

responsive to receiving a request for immobilizing the vehicle,

actuating the brake member with the actuation system to dispose the brake member in the braking configuration in a parking state in which the brake member prevents rotation of the wheel; and

engaging the brake member disposed in the parking state with a parking lock to thereby prevent the brake member from moving out of the parking state.

2. The method of claim 1 , further comprising:

causing the actuation system to cease actuating the brake member while the brake member disposed in the parking state is engaged by the parking lock.

3. The method of claim 1, wherein a maximum force exertable by the parking lock on the brake member is less than the force applied on the brake member by the actuation system to dispose the brake member in the braking configuration in the parking state.

4. The method of claim 1, wherein:

the actuation system comprises an actuation member which actuates the brake member; the actuation system applies the force on the brake member via the actuation member; and

the parking lock engages the actuation member and thereby the brake member to prevent the brake member from moving out of the parking state.

5. The method of claim 1, further comprising:

wherein the parking lock is self-locking with respect to a force exerted by the brake member on the parking lock to prevent the brake member from moving out of the parking state.

6 The method of claim 1, wherein:

the brake member is actuated along a brake actuation axis; and

the parking lock is actuated along a lock actuation axis to engage the brake member, the lock actuation axis being one of parallel to and coaxial with the brake actuation axis.

7. The method of claim 1 , further comprising:

responsive to receiving a request for stopping immobilization of the vehicle, causing the actuation system to actuate the brake member to enable the brake member to be disposed in the parking state in the absence of the parking lock engaging the brake member;

disengaging the parking lock from the brake member while actuation system actuates the brake member; and

causing the actuation system to stop actuating the brake member after disengaging the parking lock from the brake member to allow the brake member to be disposed out of the parking state.

8 The method of claim 7, wherein:

stopping actuating the brake member comprises gradually decreasing the force applied by the actuation system on the brake member.

9. The method of claim 1, wherein:

the actuation system is a hydraulic actuation system;

the force is a hydraulic force; and actuating the brake member comprises hydraulically actuating the brake member.

10. The method of claim 9, wherein hydraulically actuating the brake member with the hydraulic actuation system comprises operating a hydraulic pump to apply the hydraulic force on the brake member.

11. A braking system for a vehicle comprising a wheel, the braking system comprising:

a braking operator being configured to be operated by a driver of the vehicle for requesting slowing of the vehicle;

a vehicle immobilization operator being configured to be operated by the driver for requesting immobilization of the vehicle;

a brake assembly operatively connected to the wheel and comprising a brake member being moveable between a non-braking configuration and a braking configuration in which the brake member engages the wheel, the brake assembly being disposable in one of a slowing state in which the brake member engages the wheel so as to slow rotation thereof and a parking state in which the brake member engages the wheel so as to prevent rotation thereof; an actuation system operatively connected to the braking operator and the vehicle immobilization operator, the actuation system comprising an actuation member operatively connected to the brake member and configured to apply a force on the brake member to move the brake member between the non-braking configuration and the braking configuration and to selectively dispose the brake member in the one of slowing state and the parking state; and

a parking lock operatively connected to the vehicle immobilization operator, the parking lock being configured to selectively engage the brake member and to thereby prevent the brake member from moving out of the parking state if the brake member is engaged by the parking lock when disposed in a parking state, a maximum force exertable by the parking lock on the brake member being incapable of changing configuration of the brake member from the non-braking configuration to the parking state.

12. The braking system of claim 11, wherein the parking lock is configured to engage the brake member when the brake member is disposed in the parking state.

13. The braking system of claim 11, wherein the parking lock is self-locking.

14. The braking system of claim 13, wherein the parking lock comprises:

an output shaft configured to engage the actuation member;

an input shaft engaging the output shaft, the output shaft being moveable with respect to the input shaft; and

a parking lock motor, the input shaft being operatively connected to the parking lock motor for driving the output shaft,

the output shaft being driven by the input shaft between a disengaged position and an engaged position in which the output shaft engages the brake member with the brake member being disposed in the parking state and thereby prevents the brake member from moving out of the parking state, the output shaft being self-locking with respect to a force applied by the brake member on the output shaft.

15. The braking system of claim 14, wherein:

the brake member is actuated along a brake actuation axis;

the input shaft and the output shaft are disposed one of parallel to and coaxial with the brake actuation axis; and

the output shaft is driven along a parking lock actuation axis, the parking lock actuation axis being one of parallel to and coaxial with the brake actuation axis.

16. The braking system of claim 14, wherein the actuation member is a piston and the actuation system is a hydraulic actuation system, the hydraulic actuation system further comprising a hydraulic cylinder, the piston being disposed within the hydraulic cylinder, a central axis of the piston being disposed one of coaxial with and parallel to the input shaft and the output shaft.

17. The braking system of claim 16, wherein the piston comprises:

a first end contacting the brake member;

a second end opposite the first end and disposed inside the hydraulic cylinder; a bore extending from the second end towards the first end, at least a portion of the output shaft being disposed in the bore and selectively engaging the piston when the brake member is disposed in the parking state to prevent the brake member from moving out of the parking state.

18. The braking system of claim 16, wherein the brake member is at least one brake pad and the brake assembly is a disc brake assembly, the disc brake assembly further comprising:

a rotor mounted to the wheel to be rotatable with the wheel; and

a caliper being rotationally fixed and defining the hydraulic cylinder;

wherein the at least one brake pad is mounted to the caliper and selectively engages the rotor for braking the wheel, the at least one brake pad being operatively connected to the actuation member and the parking lock.

19. The braking system of claim 14, wherein the parking lock motor is mounted to the brake assembly.

20. The braking system of claim 11 , wherein the actuation member is a piston and the actuation system is a hydraulic actuation system comprising a hydraulic cylinder, the piston being disposed within the hydraulic cylinder.