Brake system with torque limiter assembly

Abstract

The braking system (10) sets a torque limit and includes a torque limiter assembly (48) associated with the electromechanical actuation system. The torque limiter assembly (48) includes a ring gear (62) that meshes with a planetary gear set (70), and the ring gear (62) includes a first race (86) that extends circumferentially thereof. The torque limiter assembly (48) includes a preload member having a second race (88) that extends circumferentially thereof. Balls or rollers (84) are engaged between the first race (86) and the second race (88). The first race (86) and / or the second race (88) includes a series of peaks and valleys and slopes extending therebetween. Below the torque limit, the balls or rollers (84) are engaged within the valleys, keeping the ring gear (62) rotatably captured and causing the planetary gear (70) set to orbit. Above the torque limit, the balls or rollers (84) slide over the peaks, rotating the ring gear (62) and keeping the planetary gear set (70) rotatably captured.

Description

Technical Field

[0001] Cross-Reference to Related Applications This application claims the priority benefit of U.S. Patent Application No. 17 / 878,518, filed on August 1, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a torque limiter assembly operable in conjunction with a brake system. The torque limiter assembly is associated with an electromechanical actuation system.

Background Art

[0003] Brake systems typically operate by having two or more pistons acting on brake pads to urge the brake pads into engagement with a rotor, or to release the brake pads from engagement with the rotor. The pistons generally act in unison to apply symmetrical pressure to the rotor. In some circumstances, one piston must travel a longer distance than another piston acting on the same brake pad. Accordingly, the torque applied to the pistons during an "apply" or "release" operation must be applied asymmetrically until symmetrical pressure is applied to the brake pads. If symmetrical pressure is not applied to the brake pads, insufficient braking force and uneven wear of the friction material of the brake pads may occur.

[0004] One solution to asymmetric piston movement is to use a limited slip differential, such as that described in U.S. Patent No. 9,879,739 B2. This solution requires packaging space, complex metal components, as well as precise manufacturing and assembly methods to operate reliably. Furthermore, small variations in slip torque between different pistons may cause excessive load on one or more pistons.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] U.S. Patent No. 9,879,739(B2) [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The piston assembly needs to operate asymmetrically.

[0007] A mechanism for asymmetrically operating the piston assembly must be provided within a smaller packaging space compared to that of a limited-slip differential system.

[0008] The operation of asymmetric piston assemblies needs to be addressed using a solution that requires fewer parts compared to the complexity of limited-slip differential systems.

[0009] For limited-slip differential systems, it is necessary to address the operation of asymmetric piston assemblies using relatively simple manufacturing and assembly methods. [Means for solving the problem]

[0010] This disclosure provides a braking system capable of addressing at least some of the needs identified above. The braking system may comprise an electromechanical actuation system. The electromechanical actuation system may comprise a first part and a second part. Each part may comprise a torque limiter assembly. The torque limiter assembly may set a torque limit.

[0011] Each torque limiter assembly may comprise a planetary gear set, a ring gear, a preload member, and balls or rollers. The planetary gear set may mesh with a sun gear. The ring gear may mesh with a planetary gear set. The ring gear may comprise a first race extending in its circumferential direction. The preload member may comprise a second race extending in its circumferential direction. Balls or rollers may engage between the first and second races.

[0012] The first race and / or the second race may consist of a series of peaks and valleys, as well as slopes extending between them.

[0013] Below the torque limit, the ball or roller may engage in the valley, keeping the ring gear rotatably held and causing the planetary gear set to orbit the sun gear.

[0014] Beyond the torque limit, the ball or roller may slip over the ridge, causing the ring gear to rotate and keeping the planetary gear set trapped in a circumferential position.

[0015] The angle of inclination can at least partially determine the torque limit. The angle of inclination can be between approximately 5° and approximately 45°.

[0016] The angle of inclination at which the ball or roller moves in the release direction may be the same as or different from the angle of inclination at which the ball or roller moves in the application direction.

[0017] The angle of inclination at which the ball or roller moves in the release direction can be approximately 2% to 25% greater than the angle of inclination at which the ball or roller moves in the application direction.

[0018] The torque limiter assembly may include a spring. The spring may be aligned substantially circumferentially with the first and second races. The spring may apply force to the preloading member so that the ball or roller is compressed between the preloading member and the ring gear.

[0019] The height of the peak measured from the valley may determine the torque limit. The height of the peak may determine how much the spring is compressed.

[0020] The force applied to the preload member may at least partially determine the torque limit.

[0021] The peaks, valleys, and slopes may be defined by a undulating surface, a jagged surface, or both.

[0022] Each part of the electromechanical actuation system may comprise a first plate carrier and / or a second plate carrier. The first plate carrier may engage a first side of the planetary gear set such that the track of the planetary gear set rotates the first plate carrier. The second plate carrier may engage a second side of the planetary gear set such that the track of the planetary gear set rotates the first plate carrier. The second side may be opposite to the first side.

[0023] The first or second plate carrier may comprise an output shaft that mechanically cooperates with the spindle. The spindle may cooperate with the nut as a ball screw mechanism or a conventional screw mechanism. The nut may engage the piston.

[0024] Rotation of the spindle may ultimately cause the piston to translate axially in the application direction and / or the release direction.

[0025] The torque limit of the first part may be different from the torque limit of the second part.

[0026] Both the first part and the second part of the electromechanical actuation system may be actuated by the same motor.

[0027] The brake system may include a caliper. The caliper may include an inner body portion and an outer body portion. A bridge may extend between the inner body portion and the outer body portion, and the bridge may include one or more fingers acting on the brake pad associated with the outer body portion.

[0028] The brake system may comprise two or more pistons, one entirely located on the inner body portion or the outer body portion, or one located on both the inner and outer body portions. Each of the first and second parts of the electromechanical actuation system may be associated with each of the two or more pistons.

[0029] Each part of the electromechanical actuation system may act symmetrically on two or more pistons until a torque limit is achieved by the resistance to at least one of the pistons. At that point, the electromechanical actuation system may act asymmetrically on two or more pistons due to the rotational degrees of freedom of the ring gear.

[0030] This disclosure provides an electromechanical actuation system capable of addressing at least some of the needs identified above. The electromechanical actuation system may be for vehicle brakes. The electromechanical actuation system may comprise a nut and a spindle. The rotation of the spindle may actuate the nut in the application direction and / or release direction. The electromechanical actuation system may comprise a motor. The motor may be mechanically connected to the spindle.

[0031] The electromechanical actuation system may include a torque limiter assembly. The torque limiter assembly may be mechanically positioned downstream of the motor and upstream of the spindle. The torque limiter assembly may be set to a torque limit. Below the torque limit, rotational motion may be transmitted to the spindle. Above the torque limit, rotational motion may not be transmitted to the spindle.

[0032] The torque limiter assembly may be a ball-return type torque limiter.

[0033] A torque limiter assembly may comprise a planetary gear set, a sun gear, and a ring gear. The planetary gear set may mesh with both the sun gear and the ring gear. Below the torque limit, the ring gear may remain rotatably engaged, and the planetary gear set may orbit the sun gear. Above the torque limit, the ring gear may rotate, and the planetary gear set may remain rotatably engaged.

[0034] A ring gear may comprise a race having a series of peaks and valleys, as well as inclined grooves extending between them. An electromechanical actuation system may comprise balls or rollers that engage with the race. Below the torque limit, the balls or rollers may engage in the valleys. Above the torque limit, the balls or rollers may slip over the peaks.

[0035] An electromechanical actuation system may comprise two or more parts. Each part may relate to a separate piston for engaging with a brake pad. Each part may comprise a torque limiter assembly. [Brief explanation of the drawing]

[0036] [Figure 1A] This is a perspective view of the brake system according to this instruction. [Figure 1B] This is a perspective view of the brake system according to this instruction. [Figure 1C] This is a cross-sectional view of the brake system shown in Figure 1A, along line AA. [Figure 2A] This is a perspective view of the motor gear unit and piston according to this instruction. [Figure 2B] This is a plan view of the motor gear unit and piston according to this instruction. [Figure 3A] This is a disassembled assembly diagram of the torque limiter assembly according to this instruction. [Figure 3B] This is a perspective view of the ring gear according to this instruction. [Figure 3C] This is a cross-sectional view of the ring gear shown in Figure 3B along line BB. [Modes for carrying out the invention]

[0037] This instruction provides a torque limiter assembly that can operate in conjunction with a brake system. The torque limiter assembly may be associated with an electromechanical actuation system; that is, the torque limiter assembly may be integrated into the mechanical drive mechanism of the electromechanical actuation system.

[0038] The braking system may include an electromechanical actuation system. The electromechanical actuation system may ultimately use motors to move one or more pistons in the applied and / or released directions.

[0039] The electromechanical actuation system may be associated with the operation of the service brake and / or the parking brake. Preferably, the electromechanical actuation system may be associated with the operation of the parking brake.

[0040] An electromechanical actuation system may include one or more torque limiter assemblies. The torque limiter assemblies may be mechanically installed downstream of the motor and mechanically installed upstream of the piston.

[0041] While one torque limiter assembly may be provided for each piston, this teaching anticipates that one torque limiter assembly may be associated with multiple pistons.

[0042] The braking system may include a hydraulic actuation system. The hydraulic actuation system may include a fluid that applies pressure to one or more pistons. The fluid may be disposed within a cylinder in which the pistons are housed.

[0043] The hydraulic actuation system may be associated with the operation of the service brake and / or the parking brake. Preferably, the hydraulic actuation system may be associated with the operation of the service brake.

[0044] Electromechanical actuation systems and hydraulic actuation systems may work to move pistons individually and / or cooperatively during applied and / or released operations. During applied operations, pistons may be moved toward the rotor and thus may influence the movement of one or more brake pads toward and / or to the rotor. During released operations, pistons may be moved toward the rotor and thus may influence the movement of one or more brake pads toward and / or to the rotor.

[0045] The brake system may include a caliper. The caliper may house at least part of an electromechanical actuator system and / or a hydraulic actuator system, provide mounting points for brake pads, position the brake pads relative to the rotor, or function to do any combination thereof. In this regard, the caliper may have an inner body portion and an outer body portion. The inner body portion may be located closer to the inside of the rotor. The outer body portion may be located closer to the outside of the rotor.

[0046] The caliper may be a floating caliper; that is, the caliper may be structurally separate from the electromechanical and / or hydraulic actuation system. The electromechanical and / or hydraulic actuation system may be fixed to the caliper. While fixed, the electromechanical and / or hydraulic actuation system can slide relative to the caliper.

[0047] The caliper may be a fixed caliper; that is, the caliper may be structurally integrated with the electromechanical and / or hydraulic actuation system. The electromechanical and / or hydraulic actuation system may remain fixed to the caliper.

[0048] The caliper may have both a floating portion and a fixed portion.

[0049] A braking system may comprise one or more brake pads. The brake pads may function to engage with the rotor by friction. The brake pads engage with the rotor and can slow down and / or stop the rotor and / or the vehicle on which the rotor is used. That is, the rotational motion of the rotor can be slowed down and / or stopped, and the linear motion of the vehicle can be slowed down and / or stopped.

[0050] Brake pads can be fixed to the caliper with clips or the like. Brake pads can engage with one or more pistons and thereby be moved. Preferably, the opposing ends of the brake pads can be symmetrically acted upon by the pistons. In this regard, the entire surface area of ​​the friction material on the brake pad, or at least a substantial portion of the surface area, is made to engage with the rotor. Thus, uneven wear of the brake pads can be avoided or at least mitigated, and the full intended braking load can be achieved.

[0051] A pair of brake pads may be used. The brake pads may include an inner brake pad positioned on the inner body portion of the caliper and an outer brake pad positioned on the outer body portion of the caliper. The inner and outer brake pads can clamp the rotor.

[0052] A caliper may comprise one or more cylinders. The cylinders may function to house a piston, fluids for a hydraulic actuation system, components for an electromechanical actuation system, or any combination thereof. The cylinders may be formed within the caliper by casting, machining, or both.

[0053] The brake system may comprise one or more pistons. The pistons may function to engage with the brake pads in cooperation with a hydraulic actuation system and / or an electromechanical actuation system, thereby applying a load to the brake pads. One or more components of the electromechanical actuation system (e.g., a nut and a spindle), and / or a fluid located within the cylinder, may move the pistons within the cylinder.

[0054] The piston may be located inside the cylinder. The piston may be able to move inside the cylinder. The piston may have a portion that extends outside the cylinder. The portion that extends outside the cylinder may be able to engage with the brake pads.

[0055] One or more cylinders and associated pistons may be located in or near the inner body portion. These may be referred to herein as the inner cylinder and inner piston. One or more cylinders and associated pistons may be located in or near the outer body portion. These may be referred to herein as the outer cylinder and outer piston. One or more cylinders and associated pistons may be located in or near both the inner and outer body portions. Preferably, the cylinders and associated pistons are located in or near at least the inner body portion.

[0056] The inner cylinder and associated piston may be coaxial with the outer cylinder and associated piston. In this regard, the clamping force applied by the opposing inner and outer pistons is coaxial. Such a pair of coaxial inner and outer cylinders and associated pistons may be referred to as the corresponding pair herein.

[0057] The brake system may be without one or more corresponding pairs of cylinders and associated pistons. For example, the brake system may consist only of an inner cylinder and associated piston. In another example, a corresponding pair of cylinders and associated pistons may be located in or near the first part of the caliper, and only one inner cylinder and associated piston may be located in or near the second part of the caliper. Other configurations are foreseen by this teaching.

[0058] If a portion of the caliper lacks a corresponding pair of cylinders and associated pistons, the brake system may include a bridge portion. The bridge portion may function to transfer load from the inner side of the brake system to the outer side. The bridge portion may extend across the inner and outer body portions of the caliper.

[0059] The first end of the bridge portion may be coupled to the main body portion of the brake system or to other components coupled to this main body portion. The main body portion may be slidably coupled to the caliper. The second end of the bridge portion may comprise one or more fingers. The fingers may function to engage with the brake pads. The fingers may extend from the bridge at an angle (e.g., about 90 degrees).

[0060] In the applied operation, a load may be applied to the piston by either or both an electromechanical actuation system and / or a hydraulic actuation system. Thus, the piston may be made to press the first brake pad against the rotor. Under this load, the bridge portion and fingers may be shifted axially inward, and the fingers may press the second brake pad against the rotor. The first brake pad may be an inward-facing brake pad, and the second brake pad may be an outward-facing brake pad, or vice versa. In this regard, a load is applied to both sides of the rotor (i.e., a clamping action) to decelerate and / or stop the rotor and / or the vehicle.

[0061] An electromechanical actuator system may include a motor gear unit. The motor gear unit may function to move a piston in the applied direction and / or the released direction. For this purpose, the motor gear unit may include an electrically driven motor and one or more linkage mechanisms between the motor and one or more pistons, so that the motor drives one or more linkage mechanisms, resulting in the movement of one or more pistons.

[0062] A motor gear unit may comprise a motor, one or more torque limiter assemblies, or both.

[0063] A motor gear unit may include a motor gear unit housing. The motor gear unit housing may function to protect the internal mechanism of the motor gear unit. The motor gear unit housing can house a motor, one or more torque limiter assemblies, or both. The motor gear unit housing may be supplied as one or more components positioned around the motor gear unit.

[0064] A motor gear unit may include a motor. The motor may function to actuate a piston in the application direction (i.e., toward the rotor) and / or in the release direction (i.e., toward the rotor). Examples of suitable motors that are not limited may include servo motors and stepper motors.

[0065] A motor gear unit may include a motor drive shaft. The motor drive shaft may be coupled to a motor. The motor drive shaft may extend a certain distance from the motor. The motor drive shaft may include motor drive gears arranged along its length.

[0066] A motor gear unit may comprise one or more motor drive gears. The motor drive gears may function to transmit torque generated by the motor and applied to the motor drive shaft to a torque limiter assembly. The motor drive gears may mesh with one or more torque limiter drive gears of one or more torque limiter assemblies. Non-limiting examples of suitable motor drive gears may include spur gears and helical gears.

[0067] One or more other linkage mechanisms may be disposed between the motor drive gear and one or more torque limiter assemblies. One or more other linkage mechanisms may include one or more gears, shafts, chains, belts, etc., or any combination thereof. The physical dimensions and / or arrangement of one or more other linkage mechanisms may be selected to accommodate the packaging space of the brake system. As an example, one or more gears may be disposed between the motor drive gear and one or more torque limiter assemblies to package the motor over the main body portion and / or inner body portion of the caliper while maintaining appropriate clearance from there and / or one or more torque limiter assemblies. This teaching foresees any other suitable configuration of linkage mechanisms that can mechanically connect the motor to one or more torque limiter assemblies.

[0068] A helical gear and a pinion gear may be arranged between the motor drive gear and one or more torque limiter assemblies. The helical gear and the pinion gear may share the same shaft. The helical gear and the pinion gear may rotate simultaneously. The helical gear may mesh with the motor drive gear. The pinion may mesh with one or more torque limiter assemblies. The pinion may be a spur gear.

[0069] The electromechanical actuator system may include a spindle. The spindle is mechanically connected to the torque limiter assembly and may function to axially translate a nut in the application direction and / or release direction, or both. The spindle may have threads on its outer surface. The threads may be sized to accommodate a ball or roller.

[0070] An electromechanical actuator system may include a nut. The nut may move axially along the length of the spindle, engage with a piston, and function to move this piston in the applying direction and / or the releasing direction, or any combination thereof. The nut may have threads on its inner surface. The threads may be made to a size that can accommodate a ball or roller.

[0071] A nut may be mounted on the spindle. Multiple balls or rollers and / or one or more springs may be disposed within the threads of both the spindle and the nut. The balls or rollers can provide a low-friction engagement between the nut and the spindle, rather than a direct threading, to assist the movement of the nut in the applying and / or releasing directions.

[0072] The aforementioned nut and spindle can cooperate as a ball screw mechanism. However, this teaching anticipates that other spindle and nut configurations, as well as other piston operating mechanisms, may be used in conjunction with the brake system. For example, the nut and spindle can cooperate as a conventional screw mechanism, in a conventional screw mechanism (i.e., a main screw and nut mechanism).

[0073] An electromechanical actuator system may comprise one or more torque limiter assemblies. The torque limiter assemblies may function to actuate different pistons asymmetrically. The torque limiter assemblies may be of the ball-return type.

[0074] An electromechanical actuator system may comprise one or more parts. Each part may actuate an individual piston. Preferably, two parts may be used to actuate pistons that engage with two parts of a brake pad, but the disclosure anticipates the use of fewer or more parts. Each part may comprise a torque limiter assembly. A single torque limiter assembly may be associated with two or more parts, and therefore two or more pistons.

[0075] Each part may be driven by the same motor or different motors. Preferably, each part may be driven by the same motor.

[0076] The torque limiter assembly can be set to a torque limit. The torque limit may be adjustable. Below the torque limit, a ring gear, as described herein, may remain rotatably trapped, and a planetary gear may orbit around the sun gear. Above the torque limit, the ring gear may rotate, and the planetary gear may remain rotatably trapped relative to the sun gear. The ring gear can be rotated by balls or rollers sliding over the ridges in the race of the ring gear and / or preload member. The ring gear can rotate relative to the preload member.

[0077] When one or more parts of an electromechanical actuation system reach their torque limit, the torque limiter can slip. In such a case, one or more other parts of the electromechanical actuation system can continue to actuate the spindle until their torque limits are reached. Thus, any axial misalignment between the pistons of each part of the electromechanical actuation system can be eliminated, and the respective loads applied to different parts of the brake pad can become nearly uniform.

[0078] If one or more pistons satisfy the torque limit through their engagement with one or more brake pads, one or more pistons may stop moving (for example, in the direction of application), and one or more other pistons may continue moving (for example, in the direction of application) until one or more other pistons each satisfy the torque limit.

[0079] The applied motion of a piston can be held for a certain period of time. For example, a parking brake may be applied while the vehicle is unloaded. When the electromechanical actuation system moves in the applied direction, the motor can operate until a predetermined load is met on one or more brake pads. The motor can then stop operating, and the load may be held until the electromechanical actuation system is disengaged and one or more pistons are moved in the release direction. A torque limit may be applied in the release direction while the load is held for a certain period of time.

[0080] The torque limits in the application direction and / or release direction may be between approximately 5 Nm and 30 Nm, more preferably between approximately 10 Nm and 25 Nm, or even more preferably between approximately 15 Nm and 20 Nm.

[0081] The torque limits of one or more parts of an electromechanical actuation system may be the same as, or different from, the torque limits of one or more other parts of the electromechanical actuation system.

[0082] As described herein, a ring gear and / or preload member may comprise a race having a series of peaks and valleys on a serrated surface and / or a wavy surface, and balls or rollers positioned in one or more races between the ring gear and the preload member. Below the torque limit, the balls or rollers may engage in the valleys of the serrated surface and / or wavy surface. Above the torque limit, the balls or rollers slide over the peaks of the serrated surface and / or wavy surface.

[0083] Each part of the electromechanical actuation system may act symmetrically on one or more pistons until a torque limit is achieved by the resistance to at least one of the pistons. At that point, the electromechanical actuation system may act asymmetrically on one or more pistons due to the rotational degrees of freedom of the ring gear.

[0084] A torque limiter assembly may comprise a torque limiter drive shaft and a torque limiter drive gear. The torque limiter drive shaft may function to transmit torque to a planetary gear set via a sun gear. The torque limiter drive gear may function to receive torque from a motor drive shaft and / or one or more gears of one or more other linkage mechanisms. The torque limiter drive gear may be fixed to the torque limiter drive shaft (e.g., via a keyway). The torque limiter drive shaft may be formed integrally with the torque limiter drive shaft (e.g., by casting a splined drive shaft).

[0085] The torque limiter drive shaft may include a sun gear. The sun gear may function to transmit torque from the torque limiter drive shaft to the planetary gear set. The sun gear may be mechanically positioned downstream of the torque limiter drive gear. The sun gear may be fixed to the torque limiter drive shaft (e.g., via a keyway). The sun gear may be integrally formed with the torque limiter drive shaft (e.g., by casting a splined drive shaft). The sun gear may be a spur gear. The sun gear may mesh with the planetary gear set.

[0086] A torque limiter assembly may comprise a planetary gear set. The planetary gears may function to selectively transmit torque from the torque limiter drive shaft to the output shaft. The planetary gears may orbit a sun gear. The planetary gears may mesh with the sun gear and / or a ring gear. The planetary gears may be spur gears.

[0087] The torque limiter assembly may comprise a first plate carrier and / or a second plate carrier. The first and / or second plate carriers may function to convert the orbital motion of the planetary gear into torque applied to the output shaft. The first plate carrier may be coupled to the second plate carrier. The planetary gear may be fixed between the first and second plate carriers. The first plate carrier may be located on the first side of the planetary gear, and the second plate carrier may be located on the second side opposite the planetary gear.

[0088] The first plate carrier and / or the second plate carrier may comprise one or more shafts. Planetary gears may be positioned on the shafts. The shafts may be circumferentially distributed around the first and / or second plate carriers. The planetary gears may rotate on the shafts.

[0089] One or more bushings may be positioned on the shaft between the shaft and the planetary gears. The bushings can assist the rotation of the planetary gears. The bushings can provide a less frictional surface to the direct interface between the planetary gears and the shaft.

[0090] The first or second plate carrier may include an output shaft. The output shaft may be actuated by the orbital motion of a planetary gear set. The output shaft may be coupled to a spindle. The output shaft may be splined, and the spindle may have grooves for receiving splines, or vice versa.

[0091] The torque limiter assembly may include a ring gear. The ring gear may function to rotate selectively so that the trajectory of the planetary gear can be given or denied. The ring gear may be an internal gear. The ring gear can mesh with a planetary gear set.

[0092] When the ring gear is rotatably engaged, the planetary gears can orbit the sun gear. When the ring gear is rotatably free, the torque applied to the planetary gears by the sun gear can be transmitted to the ring gear, and the planetary gears can be orbitally engaged. Therefore, the torque limit can be met when the ring gear transitions from rotatably engaged to rotatably free.

[0093] A ring gear can be rotatably trapped when a ball or roller is engaged in the groove of the ring gear's race. A ring gear can be rotatably free when a ball or roller slides over the ridge of the ring gear's race.

[0094] The torque limiter assembly may include a preloading member. The preloading member may function to apply a predetermined force to a ball or roller, to hold a ball or roller between the preloading member and the ring gear, or to do both.

[0095] The preload member may be provided with a groove. The groove may function to receive a portion of the spring. The groove may be located at the first end of the preload member opposite the second end, and the second end may be provided with a race and be very close to the ring gear.

[0096] The torque limiter assembly may include a spring. The spring may function to apply force to the preload member in the direction of the ball or roller and / or ring gear. The spring may be circumferentially aligned with the first race of the ring gear and the second race of the preload member. The spring may have a first end that engages with the preload member and a second end that engages with a spring retainer.

[0097] The force applied to the preload member can determine the torque limit. The force can be adjusted by selecting springs with different spring constants, by changing the spring preload (for example, by changing the distance between the preload member and the spring holder), or both. The spring preload can be constant or adjustable. The spring preload may be actively adjusted.

[0098] A spring can be a coil spring, a washer spring, a spring stack, an elastic element, or any combination thereof.

[0099] The torque limiter assembly may include a spring retainer. The spring retainer may function to preload the spring. The spring retainer may be a snap ring. The snap ring may engage with the inner surface of the motor gear unit housing. For example, the snap ring may fit into a groove formed on the inner surface of the motor gear unit housing. The spring retainer may be formed integrally with the motor gear unit housing by molding, casting, machining, or any combination thereof.

[0100] The ring gear may comprise a first race. The first race may function to receive balls or rollers, set torque limits, or both. The first race may extend circumferentially around the ring gear.

[0101] The preloading member may include a second race. The second race may function to receive balls or rollers, set torque limits, or both. The second race may extend circumferentially around the preloading member.

[0102] The torque limiter assembly may comprise one or more balls or rollers. The balls or rollers may function to selectively engage the ring gear. At least a portion of the balls or rollers may be located within a first race and / or a second race. The balls or rollers may be disposed between the first race of the ring gear and the second race of the preload member.

[0103] The first race and / or the second race may have undulating surfaces and / or jagged surfaces. The undulating and jagged surfaces may have peaks and valleys. The ball or roller may be trapped in a valley until a torque limit is reached. Once the torque limit is reached or exceeded, the ball or roller may slide over the peaks.

[0104] The height of the peak measured from the valley can determine the torque limit. The ball or roller can move up the slope by the height before reaching the peak and sliding into the next valley. When the ball or roller crosses this height, the spring can be compressed.

[0105] A slope can extend between peaks and valleys. A slope can be defined by angle and / or curvature. The first part of the slope can be defined by angle, and the second part of the slope can be defined by curvature.

[0106] The angle of inclination can determine the torque limit. The angle of inclination may be between about 5° and about 45°, more preferably between about 10° and about 45°, more preferably between about 15° and about 40°, or even more preferably between 20° and about 35°. Different portions of inclination directed in the same direction (i.e., the application direction or the release direction) may be defined by different or the same angle. One or more inclinations directed in the same direction of rotation may be defined by different or the same angle. The direction of rotation referred to herein with respect to a race may mean the clockwise or counterclockwise direction in which the ball or roller moves relative to the race. The application operation may include clockwise rotation, and the release operation may include counterclockwise rotation, or vice versa.

[0107] The curvature of the inclination can determine the torque limit. One or more inclinations oriented in the same direction of rotation may be defined by different curvatures or the same curvature.

[0108] The angle and / or curvature of the inclination in which the ball or roller moves in the release direction may be the same as the angle and / or curvature of the inclination in which the ball or roller moves in the application direction. In this regard, the torque limit in the release direction may be equal to the torque limit in the application direction.

[0109] The angle and / or curvature of the inclination in which the ball or roller moves in the release direction may be different from the angle and / or curvature of the inclination in which the ball or roller moves in the application direction. In this regard, the torque limit in the release direction may be greater than the torque limit in the application direction.

[0110] The angle and / or curvature of the inclination in which the ball or roller moves in the release direction may be about 2% or more, more preferably about 5% or more, or even more preferably about 10% or more, than the angle and / or curvature of the inclination in which the ball or roller moves in the application direction. The angle and / or curvature of the inclination in which the ball or roller moves in the release direction may be about 25% or less, more preferably about 20% or less, or even more preferably about 15% or less, than the angle and / or curvature of the inclination in which the ball or roller moves in the application direction.

[0111] Figures 1A to 1C show a brake system 10. The brake system 10 comprises a caliper 12 including an inner body portion 14 and an outer body portion 16. A bridge portion 18 extends from the main body portion 20 across the caliper 12. Extending from the bridge portion 18 are three fingers 22 located immediately adjacent to the outer body portion 16, although any number of fingers 22 are foreseen by this teaching. Preferably, at least two fingers 22 are used so that two opposing ends of a brake pad act upon them. The brake system 10 comprises a pair of brake pads 24 including an inner brake pad 26 and an outer brake pad 28. The inner body portion 14 and the inner brake pad 26 are located closer to the inside of the rotor. The outer body portion 16 and the outer brake pad 28 are located closer to the outside of the rotor. Although a floating caliper design is shown, this teaching may also be applied to a fixed caliper design.

[0112] As shown in Figure 1C, the brake system 10 comprises two cylinders 30 defined within a main body portion 20, with an associated piston 32 located therein and extending from there. The piston 32 moves within the cylinder 30 in the applied and released directions. The piston 32 acts on the inner brake pad 26. This teaching foresees that one or more cylinders 30 and associated pistons 32 may be located in the immediate vicinity of either or both of the inner body portion 14 and the outer body portion 16. The actuation of the piston 32 with respect to the inner brake pad 26 causes the fingers 22 to act on the outer brake pad 28. This is made possible by the main body portion 20, with a mounted bridge portion 18 slidably fixed to the caliper 12, resulting in the movement of the bridge portion 18 relative to the caliper 12. Specifically, in the applied operation, a load is applied to the piston 32 by either or both of the electromechanical actuation system 34 and / or the hydraulic actuation system. Therefore, the piston 32 is made to apply a load to the inner brake pad 26, and the inner brake pad 26 applies a load to the rotor. Then, in response to the load applied by the piston 32, the bridge portion 18 and the fingers 22 are shifted axially inward relative to the caliper 12, thereby causing the fingers 22 to press the outer brake pad 28 against the rotor. Thus, a load is applied to both opposing sides of the rotor, causing braking.

[0113] The brake system 10 of this teaching comprises at least an electromechanical actuation system 34 and optionally a hydraulic actuation system. The torque limiter assembly of this teaching is associated with the electromechanical actuation system 34. The electromechanical actuation system 34 and / or the hydraulic actuation system act on the piston 32 to move the piston 32 within the cylinder 30. Specifically, the electromechanical actuation system 34 rotates the spindle 36 while keeping it axially trapped, moving a nut 38 axially toward and away from the inner brake pad 26, the nut 38 engaging with the piston 32 and causing the piston 32 to move. The hydraulic actuation system causes the fluid 40 present in the cylinder 30 to apply or release hydraulic pressure to the piston 32. The electromechanical actuation system 34 and the hydraulic actuation system can work individually and / or cooperate with each other during the application and release operations. Typically, the electromechanical actuation system 34 operates the parking brake and the hydraulic actuation system operates the service brake, but other configurations are foreseen by this teaching.

[0114] The electromechanical actuation system 34 includes a motor gear unit 42, which is coupled to the main body portion 20 of the brake system 10. The motor gear unit 42 includes a motor gear unit housing 44 that covers and protects the internal mechanism of the motor gear unit 42.

[0115] Figures 2A and 2B show the motor gear unit 42 with the motor gear unit housing 44 shown in Figures 1A to 1C removed. The motor gear unit 42 comprises a motor 46 and two torque limiter assemblies 48. One torque limiter assembly 48, or three or more torque limiter assemblies 48, are also foreseen by this teaching. Generally, one torque limiter assembly 48 is associated with each individual piston 32. The motor 46 comprises a motor drive shaft 50 including a motor drive gear 52, which acts on a helical gear 54, which shares a common shaft with a pinion gear 56. Torque is transmitted from the motor drive shaft 50 to the torque limiter assemblies 48 via the motor drive gear 52, the helical gear 54, and the pinion gear 56. This disclosure anticipates that any number of linkage mechanisms (e.g., gears) may be used between the motor drive shaft 50 and the torque limiter assembly 48. For example, the motor drive shaft 50 may be splined and directly engage with the torque limiter assembly 48. The number and arrangement of linkage mechanisms may be guided by the desired packaging space of the components of the brake system 10. As shown in Figures 2A and 2B, helical gears and pinion gears 56 result in the motor 46 being packaged above the cylinder 30 shown in Figure 1C.

[0116] Figure 2B provides an alternative diagram of the motor gear unit 42 shown in Figure 2A. Each torque limiter assembly 48 comprises a torque limiter drive gear 58 coupled to a torque limiter drive shaft 60. Each torque limiter assembly 48 comprises a ring gear 62 cooperating with a planetary gear 70 driven by a sun gear 72 shown in Figure 3A, the sun gear 72 being related to the torque limiter drive shaft 60. The ring gear 62 engages with a ball 84 shown in Figure 3A and is sandwiched between the ring gear 62 and the first side of a preload member 64. The preload member 64 is radially fixed within the motor gear unit housing 44 shown in Figure 1C. A spring 66 engages the preload member 64 with its corresponding second side. The spring 66 is held in the engaged state with the preload member 64 by a spring retainer 68. The spring retainer 68 is coupled to the inner surface of the motor gear unit housing 44 shown in Figures 1A to 1C, extending from there and providing a surface for the spring 66 to engage.

[0117] Figure 3A shows a torque limiter assembly 48. The torque limiter assembly 48 comprises a ring gear 62 cooperating with three planetary gears 70 driven by a sun gear 72. The sun gear 72 is in the form of a spline with respect to the torque limiter drive shaft 60. The sun gear 72 may be integrally formed with the torque limiter drive shaft 60 (e.g., by casting and / or machining) or fixed thereto (e.g., by key engagement). The sun gear 72 acts the planetary gears 70 relative to the ring gear 62. Although three planetary gears 70 are shown, this teaching anticipates fewer or more planetary gears 70.

[0118] The planetary gear 70 is fixed between a first plate carrier 74 and a second plate carrier 76. The first plate carrier 74 comprises three shafts 78 extending therefrom, the shafts 78 comprising bushings 80 to facilitate the rotation of the planetary gear 70. This teaching foresees that the shafts 78 extend from either or both of the first plate carrier 74 and the second plate carrier 76. The second plate carrier 76 comprises an output shaft 82.

[0119] The ring gear 62 engages with a ball 84 sandwiched between the ring gear 62 and the first side of the preload member 64. The spring 66 engages with the preload member 64 on its opposing second side. The spring 66 is held in the engaged state with the preload member 64 by a spring retainer 68. The spring retainer 68 is located very close to the torque limiter drive gear 58.

[0120] The ring gear 62 includes a first race 86 that extends circumferentially around the ring gear 62. Adjacent to the ring gear 62, a preload member 64 is provided, which includes a second race 88 that is in a position opposite to the first race 86.

[0121] The preload member 64 is provided with a groove 90 facing the second race 88. The first end of the spring 66 is located within the groove 90. The second end of the spring 66, opposite the first end, abuts against the spring holder 68.

[0122] As shown in Figures 3B and 3C, the first race 86 of the ring gear 62 has a wavy surface 92. The disclosure anticipates that a second race 88 associated with a preload member 64 may have a wavy surface 92 in addition to or as an alternative to the first race 86. The wavy surface 92 comprises a series of peaks 94 and valleys 96 and inclinations 98 extending between them. The plurality of balls 84 shown in Figure 3A may be located between and within the first race 86 and the second race 88. There may be a number of balls 84 corresponding to the number of valleys 96, or there may be a number of balls less than the number of valleys 96.

[0123] Returning to Figure 3A, the spring 66 applies force to the preloaded member 64, thus holding the ball 84 within the valley 96. As described herein, the preload of the spring 66, the angle of the inclination 98, the number of balls 84, the dimensions of the balls 84 (e.g., diameter), the height of the crests 94 measured from the valley 96, or any combination thereof, can determine the torque limit required for the ball 84 to slide over the crests 94 of the undulating surface 92. Other configurations that determine the torque limit can be understood from this teaching.

[0124] Below the torque limit, the engagement of the balls 84 in the grooves 96 fixes the position of the ring gear 62, preventing it from rotating. In this configuration, the planetary gears 70 orbit the sun gear 72. Above the torque limit, the balls 84 slip over the peaks 94, causing the ring gear 62 to rotate. In this configuration, the planetary gears 70 rotate relative to their respective shafts 78, but they do not orbit the sun gear 72. Instead of the planetary gears orbiting the sun gear 72, the ring gear 62 orbits the sun gear 72.

[0125] The descriptions and examples provided herein are intended to inform those skilled in the art of the present invention, its principles, and its practical applications. Those skilled in the art can adapt and apply the present invention in its many forms to best suit the requirements of a particular use.

[0126] The above description is intended to be illustrative and not limiting. Many embodiments and uses other than those given will be apparent to those skilled in the art by reading the above description.

[0127] Other combinations are also possible, as can be found in the following claims, and these are also incorporated herein by reference.

[0128] Therefore, the scope of the present invention should not be determined by reference to the above description, but rather by reference to the appended claims, together with the entire scope equivalent to that which is granted by such claims.

[0129] The omission of any aspect of the subject matter disclosed herein in the following claims shall not be deemed an abandonment of such subject matter, nor should it be deemed that the inventors did not consider such subject matter to be part of the subject matter of the disclosed invention.

[0130] Multiple elements may be provided by a single, unified element, or one element may be split into multiple elements.

[0131] The disclosure of "one (a)" or "one (one)" to describe an element is not intended to exclude additional elements.

[0132] Terms such as "first," "second," and "third" may be used herein to describe various elements, components, areas, and / or sections, but these elements, components, areas, and / or sections should not be limited by these terms. These terms may be used to distinguish one element, component, area, and / or section from another. Terms such as "first," "second," and other numerical terms, when used herein, do not imply order or sequence unless explicitly indicated by the context. Thus, a first element, component, area, and / or section described above or below may be referred to as a second element, component, area, and / or section without departing from this teaching.

[0133] Spatially relative terms such as “inside,” “outside,” “directly below,” “downward,” “below,” “up,” and “upper” may be used herein to facilitate explanation in describing the relationship between one element or feature and another, as shown in the figures. Spatially relative terms may be intended to encompass different orientations of a device in use or operation, in addition to the orientations shown in the figures. For example, if the device in the figure is turned upside down, the element described as “below” or “directly below” the other element or feature will then be oriented “up” the other element or feature. Thus, the illustrative term “down” may encompass both upward and downward orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptive terms used herein will be interpreted accordingly.

[0134] The terms “approximately” or “substantially” used to describe an angle measurement may mean approximately + / -10° or less, approximately + / -5° or less, or even approximately + / -1° or less. The terms “approximately” or “substantially” used to describe an angle measurement may mean approximately + / -0.01° or more, approximately + / -0.1° or more, or even approximately + / -0.5° or more.

[0135] The use of "about" or "approximately" in relation to a range applies to both ends of the range. Therefore, "about 20 to 30" is intended to encompass "about 20 to about 30" that includes at least the specified endpoint.

[0136] Unless otherwise specified, any numerical values ​​described herein include all values ​​from the lowest to the highest in increments of one unit, provided that there is at least a two-unit gap between any lowest and highest value. For example, if a value is stated to be, for example, 1 to 90, 20 to 80, or 30 to 70, then intermediate range values ​​such as (e.g., 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc.) are intended to be within the range of this teaching. For values ​​less than 1, one unit is considered to be 0.0001, 0.001, 0.01, or 0.1, as necessary. These are merely examples of what is specifically intended, and all possible combinations of numerical values ​​between the lowest and highest values ​​listed should be considered to be expressly described in this application as well. Unless otherwise specified, all ranges include all numbers at both endpoints and between the endpoints.

[0137] The term “essentially consisting of” used to describe a combination shall include the identified element or component, and other elements or components that do not substantially affect the basic and novel characteristics of the combination. The use of the terms “comprising” or “including” used to describe a combination of elements or components in this specification also foreshadows embodiments that essentially consist of elements or components.

[0138] All disclosures of articles and references, including patent applications and publications, are incorporated by reference for all purposes. [Explanation of symbols]

[0139] 10 Brake System 12 calipers 14 Inner body part 16 Outer body part 18 Bridge section 20 Main body part 22 Fingers 24 pairs of brake pads 26 Inner brake pads 28 Outer brake pads 30 cylinders 32 pistons 34. Electromechanical Actuation Systems 36 spindles 38 nuts 40 fluid 42 Motor Gear Unit 44 Motor gear unit housing 46 Motor 48 Torque limiter assembly 50 Motor drive shaft 52 Motor drive gear 54 Helical gear 56 pinion 58 Torque limiter drive gear 60 Torque limiter drive shaft 62 Ring gears 64 Preloading member 66 springs 68 Spring retainer 70 Planetary gear 72 Sun Gear 74. First Plate Carrier 76. Second plate carrier 78 Shaft 80 Bush 82 Output shaft 84 balls 86 Race 1 88 Second Race 90 grooves 92 Wavy surface 94 Mountain 96 Valley 98 Slope

Claims

1. In the braking system, The brake system comprises an electromechanical actuation system having at least a first part and a second part, each part being The system includes a torque limiter assembly for setting the torque limit, and the torque limiter assembly is A set of planetary gears that mesh with the sun gear, A ring gear having a first race that meshes with the aforementioned planetary gear set and extends in the circumferential direction, A preload member having a second race extending in the circumferential direction, It comprises a ball or roller engaged between the first race and the second race, The first race and / or the second race comprises a series of peaks and valleys, as well as slopes extending between them, Below the torque limit, the ball or roller engages in the valley, preventing the ring gear from rotating and causing the planetary gear set to orbit around the sun gear. A braking system that, when the torque exceeds the aforementioned torque limit, causes the ball or roller to slip over the ridge, thereby rotating the ring gear and preventing the planetary gear set from rotating.

2. The brake system according to claim 1, wherein the angle of the inclination at least partially determines the torque limit, and the angle of the inclination is between about 5° and about 45°.

3. The brake system according to claim 2, wherein the angle of the inclination by which the ball or roller moves in the release direction is the same as or different from the angle of the inclination by which the ball or roller moves in the application direction.

4. The brake system according to claim 2, wherein the angle of the inclination by which the ball or roller moves in the release direction is about 2% to 25% greater than the angle of the inclination by which the ball or roller moves in the application direction.

5. The torque limiter assembly is A spring aligned substantially circumferentially with the first and second races, which applies force to the preloading member so that the ball or roller is compressed between the preloading member and the ring gear. A brake system according to claim 1 or 2, comprising:

6. The brake system according to claim 5, wherein the height of the peak measured from the valley determines at least partially the torque limit.

7. The brake system according to claim 1 or 2, wherein the aforementioned peaks, valleys, and slopes are determined by the undulating surface.

8. Each part of the aforementioned electromechanical actuation system is: A first plate carrier comprising a first plate carrier which engages with a first side of the planetary gear set such that the orbit of the planetary gear set rotates the first plate carrier, A second plate carrier comprising a second plate carrier which engages with a second side of the planetary gear set such that the orbit of the planetary gear set rotates the second plate carrier, the second side being opposite to the first side, The brake system according to claim 1 or 2.

9. The brake system according to claim 8, wherein the first or second plate carrier comprises an output shaft that mechanically cooperates with a spindle, the spindle cooperating with a nut as a ball screw mechanism or a conventional screw mechanism, and the nut engages with a piston.

10. The braking system according to claim 9, wherein the rotation of the spindle ultimately causes the piston to move axially in parallel in the application direction and / or release direction.

11. The brake system according to claim 1 or 2, wherein the torque limit of the first portion is different from the torque limit of the second portion.

12. The brake system according to claim 1 or 2, wherein both the first and second parts of the electromechanical actuation system are actuated by the same motor.

13. The caliper comprises an inner body portion and an outer body portion, The bridge extends between the inner body portion and the outer body portion, The bridge comprises one or more fingers that act on the brake pad associated with the outer body portion. The brake system according to claim 1 or 2.

14. The system comprises two or more pistons that are positioned entirely on the inner body portion or the outer body portion, or that are positioned on both the inner body portion and the outer body portion. Each of the first and second parts of the electromechanical actuation system is associated with each of the two or more pistons. The brake system according to claim 13.

15. Each part of the electromechanical actuation system acts symmetrically on the two or more pistons until the torque limit is achieved by resistance to at least one of the pistons, and when the torque limit is achieved, the electromechanical actuation system acts asymmetrically on the two or more pistons due to the rotational degrees of freedom of the ring gear. The brake system according to claim 14.

16. In an electromechanical actuation system for vehicle brakes, the electromechanical actuation system is A nut and a spindle, wherein the rotation of the spindle causes the nut to move in the application direction and the release direction, A motor mechanically connected to the aforementioned spindle, A torque limiter assembly mechanically disposed downstream of the motor and upstream of the spindle, the torque limiter assembly comprising a planetary gear set, a sun gear, and a ring gear, wherein the planetary gear set meshes with both the sun gear and the ring gear, The torque limiter assembly is set to a torque limit, and below the torque limit, rotational motion is transmitted to the spindle, and above the torque limit, rotational motion is not transmitted to the spindle. Below the torque limit, the ring gear does not rotate, and the planetary gear set revolves around the sun gear. An electromechanical actuation system in which, above the aforementioned torque limit, the ring gear rotates, and the planetary gear set does not rotate.

17. The electromechanical actuation system according to claim 16, wherein the torque limiter assembly is a ball-return type torque limiter.

18. The torque limiter assembly comprises a ring gear, the ring gear comprising a race having a series of peaks and valleys, and inclined grooves extending between them, and the electromechanical actuation system comprising a ball or roller engaged with the race, wherein below the torque limit, the ball or roller engages in the valley, and above the torque limit, the ball or roller slides over the peak. The electromechanical actuation system according to claim 16 or 17.

19. The electromechanical actuation system according to claim 16 or 17, comprising two or more parts, each part relating to a separate piston for engaging with a brake pad, and each part comprising the torque limiter assembly.

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