Electromechanical brake and braking method

Abstract

The invention discloses an electronic mechanical brake. The brake comprises a driving motor, a gearbox assembly, a caliper assembly, a brake support and a friction plate. The axis of the driving motor is parallel to the axis of the caliper assembly, and the driving motor is used for achieving driving and stopping of the brake. The gear box assembly comprises a gear transmission system, and torque needed by braking is provided through the driving motor. The caliper assembly is a main body structure of the brake, provides shell protection and converts the torque of the gear box assembly into axial movement; the friction plates are installed in the brake support and comprise the inner friction plate and the outer friction plate, and the inner friction plate and the outer friction plate move oppositely and clamp the brake disc in the braking process, so that vehicle braking torque is generated. The invention further discloses a braking method using the brake.

Description

Technical Field

[0001] The invention belongs to the technical field of brake devices and relates to an electromechanical brake and a braking method. Background Art

[0002] Electromechanical brakes are used in vehicle braking systems. With the advent of new technologies such as vehicle electrification and autonomous driving, new demands have been placed on the electrification of vehicle braking systems.

[0003] The traditional vehicle braking system adopts a hydraulic braking system. During the braking process, the driver needs to use the brake pedal and pressurize the braking system to achieve the braking function. This traditional braking system is not very conducive to the realization of functions such as vehicle automatic driving. The traditional hydraulic braking system includes a hydraulic brake, a brake pipe, a brake master cylinder for driving, a booster and a related control unit. Among them, the hydraulic brake adopts the form of hydraulically pushing the piston to move. A piston is arranged inside the cylinder hole of the housing. During the braking process, the friction plate is pushed by hydraulic pressure to fit the brake disc to achieve the braking function. This system adopts a purely mechanical form, and the brake is relatively simple. However, in order for the brake to work, the brake master cylinder, booster and other control units and brake pipes need to cooperate with each other to complete it, and the entire braking system is relatively complicated. At the same time, the purely mechanical structure is not conducive to the development of vehicle automation and electronic control.

[0004] With the development of electric vehicles and hybrid technology, new requirements have been put forward for the electronic control of vehicle braking systems. The use of electromechanical brakes directly driven by motors is a good technical route. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide an electromechanical brake and a braking method to realize the electronic control of the braking system. The vehicle braking is transmitted to the braking system controller in the form of an electrical signal, and the vehicle braking function is realized by driving the braking system through an electronically controlled motor. At the same time, the application of the electromechanical brake also makes the braking structure of the whole vehicle relatively simple.

[0006] The present invention can meet the following requirements by using an electromechanical brake:

[0007] 1. The electronic control of vehicle braking system can provide technical conditions for autonomous driving;

[0008] 2. Simplify the structure of the vehicle braking system, and the system matching is relatively simple.

[0009] The electromechanical brake simplifies the traditional brake hydraulic system into a transmission system driven by a DC motor. The braking function is achieved through the DC motor driving the gearbox, which amplifies the motor torque and transmits it to the ball screw mechanism; the ball screw converts the motor torque into linear thrust and pushes the brake friction plate to fit the traditional brake disc to achieve the vehicle braking function.

[0010] The present invention provides an electromechanical brake, such as Figure 1 As shown, the drive motor outputs a torque, which is amplified and transmitted through the gear box assembly. The gear box assembly transmits the torque to the ball screw assembly, and the ball screw assembly converts the torque into axial movement to control the extension of the piston, thereby realizing the caliper clamping function in the brake bracket.

[0011] The present invention provides an electromechanical brake, which comprises: a driving motor, a gear box assembly, a caliper assembly, a brake bracket, and a friction plate;

[0012] The axis of the driving motor is parallel to the axis of the caliper assembly, and is used to realize the driving and releasing of the brake;

[0013] The gearbox assembly includes a gear transmission system, and the drive motor provides the torque required for braking;

[0014] The caliper assembly is the main structure of the brake, providing housing protection and converting the torque of the gearbox assembly into axial motion;

[0015] The friction plate is installed in the brake bracket, and includes an inner friction plate and an outer friction plate. During braking, the inner and outer friction plates move toward each other and clamp the brake disc, thereby generating a vehicle braking torque.

[0016] The gearbox assembly is mounted on the caliper assembly via MGU screws; the caliper assembly is connected to the brake bracket via flange bolts.

[0017] The caliper assembly includes a snap ring, a housing, a force feedback unit, a thrust bearing, a snap spring, a ball screw assembly, a piston, a sealing ring, a dust cover, and a stop bolt;

[0018] The ball screw assembly includes a screw, a screw collar, and a nut; the screw includes a screw shaft with a screw spline on the top and a screw inner shaft with a thread;

[0019] The clamping ring is assembled through its inner ring and the lead screw shaft portion by interference fit and press-fit, and is used to prevent the lead screw spline at the top end of the lead screw shaft and the matching spline in the gear box from coming out;

[0020] The housing is integrally formed, and a housing cylinder hole for accommodating a ball screw assembly is provided in the middle; during operation, the positions of the drive motor, the gear box assembly, and the housing remain relatively fixed, and the drive motor, the gear box assembly, and the housing can move relative to the brake bracket; a stop hole is also provided on the housing for inserting a stop bolt.

[0021] The screw shaft ring is annular as a whole, and an internal spline is arranged in the middle. The size of the internal spline is larger than the diameter of the screw shaft and smaller than the diameter of the screw inner shaft. The screw shaft ring is sleeved on the screw shaft, and the position where the screw shaft ring contacts the screw is processed into a concave spherical surface; the nut is a hollow cylinder that passes through from top to bottom as a whole, and is sleeved on the screw inner shaft. The outer edge of the bottom is processed into a convex spherical surface, which corresponds to the concave spherical surface processed and arranged in the piston;

[0022] The position on the inner shaft of the lead screw that intersects with the lead screw optical axis is designed to be a convex spherical surface that matches the concave spherical surface of the lead screw shaft ring.

[0023] The relative positions of the screw collar and the nut are respectively provided with right-angled triangle-shaped boss features, namely the collar boss feature and the nut boss feature. The two vertical right-angled sides of the collar boss feature and the nut boss feature can ensure the vertical fit of the two by adjusting the angle of the internal spline of the screw collar.

[0024] The middle opening of the force feedback unit is positioned and installed on the lead screw optical axis, and is matched with the lead screw optical axis in a clearance manner, so that the clamping force can be fed back to the control system in real time, and the force feedback unit does not rotate during the transmission process; the force feedback unit includes an outer gasket, a force sensor, and a stop gasket; the stop gasket is also provided with a stop groove, which can stop the rotation of the stop gasket by inserting and withdrawing a stop bolt.

[0025] A thrust bearing is also installed between the force feedback unit and the lead screw collar, and the thrust bearing is used to bear the axial thrust generated by the brake during operation and reduce the friction between the lead screw collar and the anti-rotation washer;

[0026] The retaining spring is installed between the nut and the piston to fix the nut and the piston together, so that the piston and the nut are relatively fixed, so that the piston can be returned through the ball screw assembly without relying on the return of the rectangular sealing ring, thereby achieving the low drag requirement.

[0027] The outer gasket and the anti-rotation gasket cooperate with the force sensor through the end faces. During the transmission process, the screw rotates, generating an axial thrust on the screw shaft ring, causing the thrust bearing to rotate, and applying the axial thrust to the anti-rotation gasket, thereby generating a positive bearing pressure on the force sensor, and the generated pressure is output through the force sensor; the thrust bearing and the anti-rotation gasket cooperate and rotate on the end face of the anti-rotation gasket, and the anti-rotation gasket will have a tendency to rotate under the action of the rotational friction force, and the anti-rotation gasket cooperates with the anti-rotation groove arranged on the anti-rotation gasket and the anti-rotation bolt arranged on the housing to prevent the anti-rotation gasket from rotating during the transmission process.

[0028] The piston is generally in the shape of a hollow cylinder with one side open, and is sleeved on the outside of the ball screw assembly. The inside of the piston and the corresponding position of the convex spherical surface at the bottom edge of the nut are processed into a concave spherical surface matching the convex spherical surface;

[0029] The rectangular sealing ring is arranged between the housing and the piston to provide rubber damping to reduce impact noise and knock;

[0030] The dust cover is installed near the bottom of the piston and is designed to be pleated. The pleated design can meet the dust protection requirements under all working conditions.

[0031] The extension line of the force-bearing surface of the screw rod spline passes through the center of the circle, or the extension line of the force-bearing surface is within the φ1.5mm area of ​​the center of the circle.

[0032] The present invention also proposes a braking method using the above brake, comprising the following steps:

[0033] Step 1: The driving motor drives the gearbox assembly to amplify the torque;

[0034] Step 2: The gearbox assembly drives the ball screw assembly to rotate through the meshing splines;

[0035] Step 3: The ball screw assembly converts the torque of the gearbox assembly into an axial thrust along the cylinder bore of the housing and generates a positive pressure on the piston;

[0036] Step 4: The piston is displaced toward the friction plate;

[0037] Step 5: The displacement and force of the piston continue to increase under the action of the gearbox assembly, and the friction plate presses the brake disc to generate the pressure required for braking, thereby realizing the braking function.

[0038] The beneficial effects of the present invention include:

[0039] 1. Simplify the vehicle braking system architecture.

[0040] 2. Electronic braking provides a basis for autonomous driving, etc.

[0041] 3. Improve braking efficiency.

[0042] 4. Reduce the energy loss caused by vehicle drag and improve vehicle endurance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 It is the overall structural diagram of the electromechanical brake of the present invention.

[0045] Figure 2 It is a schematic diagram of the internal disassembled structure of the caliper assembly of the present invention.

[0046] Figure 3 From top to bottom are respectively a front view of the electromechanical brake of the present invention and a cross-sectional view along the AA plane.

[0047] Figure 4 It is a schematic diagram of the overall structure of the force feedback unit of the present invention and a schematic diagram of the disassembled structure.

[0048] Figure 5 From left to right are respectively a bottom view of the electromechanical brake of the present invention and a cross-sectional view along plane BB.

[0049] Figure 6 From left to right are two stereoscopic views of the ball screw assembly and the piston structure of the present invention, a front view, and a cross-sectional view along the CC plane.

[0050] Figure 7 It is a disassembly schematic diagram of the nut, the retaining spring and the piston of the present invention, as well as a specific structural schematic diagram of the retaining spring, the nut and the piston.

[0051] Figure 8 It is a schematic diagram of the transmission structure of the prior art.

[0052] Fig. 9 It is a schematic diagram of the spherical structure between the lead screw and the lead screw shaft ring, and between the lead screw sleeve and the piston in the ball screw assembly of the present invention.

[0053] Fig.10 It is a cross-sectional schematic diagram of a screw spline machined on a screw shaft in a ball screw assembly in the present invention, wherein an extension line of a force-bearing surface of the screw spline passes through the center of a circle, or the extension line of the force-bearing surface is tangent to a circle with a center of φ1.5 mm.

[0054] Fig.11From left to right are respectively a schematic diagram of radial sealing between the caliper and the MGU in the prior art and a diagram of the actual structure.

[0055] Fig.12 From left to right are respectively a schematic diagram of the axial seal between the caliper and the MGU of the present invention and a diagram of the actual structure.

[0056] Fig.13 From left to right are the MGU sealing ring installed in the gearbox assembly housing and the structural diagram of the housing, MGU sealing ring and gearbox assembly.

[0057] Fig.14 From left to right are the structural schematics of the ball screw unit, screw shaft ring, and nut.

[0058] Fig.15 From left to right are the schematic diagrams of the MGU sealing ring, anti-rotation bolt, anti-rotation gasket, rectangular sealing ring, and dust cover structure.

[0059] Fig.16 From left to right are the top view of the connection between the shell and the bracket and the cross-sectional view along the EE plane.

[0060] Fig.17 It is a schematic diagram of the position of the claw and the cylinder hole when the shell is loaded or unloaded. The left figure shows the shell is not loaded, and the claw is perpendicular to the cylinder hole; the right figure shows the shell is loaded, and the claw is not perpendicular to the cylinder hole.

[0061] In the figure, 1-drive motor, 2-gearbox assembly, 2.1-MGU sealing ring, 3-caliper assembly, 3.1-snapping ring, 3.2-housing, 3.2.1-stop hole, 3.3-force feedback unit, 3.3.1-external gasket, 3.3.2-force sensor, 3.3.3-stop gasket, 3.3.3.1-stop groove, 3.4-thrust bearing, 3.5-circlip, 3.6-ball screw assembly, 3.6.1-screw, 3.6.1.1-screw optical axis, 3.6.1.2-screw Inner shaft, 3.6.1.3-screw spline, 3.6.2-screw collar, 3.6.2.1-inner spline, 3.6.2.2-collar boss feature, 3.6.3-nut, 3.6.3.1-nut boss feature, 3.7-piston, 3.7.1-circlip mounting groove, 3.8-rectangular sealing ring, 3.9-dust cover, 3.10-stop bolt, 4-brake bracket, 5-friction plate, 5.1-friction plate outer plate, 5.2-friction plate inner plate, 6-MGU screw, 7-flange bolt. DETAILED DESCRIPTION

[0062] The present invention is further described in detail with reference to the following specific examples and drawings. The process, conditions, experimental methods, etc. for implementing the present invention, except for the contents specifically mentioned below, are all common knowledge and common common sense in the art and are not particularly limited by the present invention.

[0063] The present invention provides an electromechanical brake, such as Figure 1 As shown, the drive motor 1 outputs a torque, which is amplified and transmitted through the gear box assembly 2. The gear box assembly 2 transmits the torque to the ball screw assembly 3.6, and the ball screw assembly 3.6 converts the torque into axial movement to control the extension of the piston 3.7, thereby realizing the caliper clamping function in the brake bracket.

[0064] The electromechanical brake comprises a drive motor 1, a gearbox assembly 2, a caliper assembly 3, a brake bracket 4, and a friction plate 5; the friction plate further comprises an outer friction plate 5.1 and an inner friction plate 5.2;

[0065] The axis of the driving motor 1 is parallel to the axis of the caliper assembly 3, and is used to realize the driving and stopping of the brake;

[0066] The gearbox assembly 2 includes a gear transmission system, and the drive motor 1 provides the torque required for braking;

[0067] The caliper assembly 3 is the main structure of the brake, providing housing protection and converting the torque of the gearbox assembly 2 into axial motion;

[0068] The gearbox assembly 2 is mounted on the caliper assembly 3 by means of an MGU screw 6; an MGU sealing ring 2.1 is further provided between the gearbox assembly 2 and the caliper assembly 3. Specifically, an MGU sealing ring groove is provided on the housing of the caliper and is machined and formed. The MGU sealing ring 2.1 is provided in the MGU sealing ring groove for waterproof and oil-proof sealing therebetween; the caliper assembly 3 is connected to the brake bracket 4 by means of a flange bolt 7;

[0069] like Figure 2 As shown, the caliper assembly 3 further includes a snap ring 3.1, a housing 3.2, a force feedback unit 3.3, a thrust bearing 3.4, a snap spring 3.5, a ball screw assembly 3.6, a piston 3.7, a rectangular sealing ring 3.8, a dust cover 3.9, and a stop bolt 3.10;

[0070] The installation position of the clamping ring 3.1 is shown in Figure 3, the retaining ring is assembled together through its inner ring and the screw shaft part by interference fit. Its purpose is to prevent the screw spline 3.6.1.3 at the top of the screw shaft and the matching spline in the gearbox from coming out. There are three possible movement states of the screw shaft and the screw sleeve when the caliper is released. The first is that the screw shaft moves toward the screw sleeve, the second is that the screw shaft and the screw move together, and the third is that the screw sleeve moves toward the screw shaft. In the first and second cases, the screw shaft will produce a large displacement, and the top spline meshing part has the risk of disengagement. The purpose of the retaining ring 3.1 is to limit the movement of the screw shaft and change the situation to the required third working condition.

[0071] The housing 3.2 is integrally formed, and a housing cylinder hole for accommodating the ball screw assembly 3.6 is provided in the middle; during operation, the positions of the drive motor 1, the gear box assembly 2, and the housing 3.2 remain relatively fixed, and the drive motor 1, the gear box assembly 2, and the housing 3.2 can move relative to the brake bracket 4; a stop hole 3.2.1 is also provided on the housing 3.2 for inserting a stop bolt 3.10;

[0072] like Fig.14 As shown, the ball screw assembly 3.6 further includes a screw 3.6.1, a screw collar 3.6.2, and a nut 3.6.3;

[0073] The screw 3.6.1 is further divided into two parts, one part is a screw shaft 3.6.1.1 with a screw spline 3.6.1.3 on the top, and the other part is a screw inner shaft 3.6.1.2 with a thread; the screw shaft ring 3.6.2 is annular as a whole, and an internal spline 3.6.2.1 is arranged in the middle, and the size of the internal spline 3.6.2.1 is larger than the diameter of the screw shaft 3.6.1.1 and smaller than the diameter of the screw inner shaft 3.6.1.2, the screw shaft ring 3.6.2 is sleeved on the screw shaft 3.6.1.1, and the position where the screw shaft ring 3.6.2 contacts the screw 3.6.1 is processed into a concave spherical surface; the screw shaft ring 3.6.2 serves as a bearing platform for bearing axial thrust ; The nut 3.6.3 is a hollow cylinder that penetrates from top to bottom as a whole, and is sleeved on the inner shaft 3.6.1.2 of the screw, and the outer edge of the bottom is processed into a convex spherical surface, which corresponds to the concave spherical surface processed and set in the piston 3.7; The relative positions of the screw collar 3.6.2 and the nut 3.6.3 are respectively provided with right-angled triangle-shaped boss features, namely the collar boss feature 3.6.2.2 and the nut boss feature 3.6.3.1, and the two vertical right-angled sides of the collar boss feature 3.6.2.2 and the nut boss feature 3.6.3.1 can ensure that the vertical surfaces of the two fit together by adjusting the angle of the internal spline 3.6.2.1 of the screw collar; if the boss feature is not used, the starting torque is large and there is a risk of jamming;

[0074] Figure 6 From left to right are two stereoscopic views of the ball screw assembly and the piston structure of the present invention, a front view, and a cross-sectional view along the CC plane.

[0075] Furthermore, the position on the inner shaft 3.6.1.2 of the screw that intersects with the optical axis 3.6.1.1 of the screw is designed to be a convex spherical surface that matches the concave spherical surface of the screw collar 3.6.2.

[0076] The force feedback unit 3.3 is positioned and installed on the screw shaft 3.6.1.1 with a middle opening, and is clearance-matched with the screw shaft 3.6.1.1, so as to be able to provide real-time feedback of the clamping force to the control system. The force feedback unit 3.3 does not rotate during the transmission process; Figure 4 As shown, the force feedback unit includes an outer gasket 3.3.1, a force sensor 3.3.2, and a rotation-stopping gasket 3.3.3; the rotation-stopping gasket is also provided with a rotation-stopping groove 3.3.3.1, which can stop the rotation of the rotation-stopping gasket 3.3.3 by inserting a rotation-stopping bolt 3.10; Figure 5 From left to right are respectively a bottom view of the electromechanical brake of the present invention and a cross-sectional view along plane BB.

[0077] A thrust bearing 3.4 is also installed between the force feedback unit 3.3 and the screw shaft ring 3.6.2;

[0078] The thrust bearing 3.4 is used to bear the axial thrust generated by the brake during operation and reduce the friction between the screw shaft ring 3.6.2 and the anti-rotation washer 3.3.3.

[0079] The retaining spring 3.5 is installed between the nut 3.6.3 and the piston 3.7, specifically in the retaining spring installation groove 3.7.1 of the piston 3.7, to fix the nut 3.6.3 and the piston 3.7 together, so that the piston 3.7 and the nut 3.6.3 are relatively fixed, so that the piston 3.7 can be returned by the ball screw assembly 3.6, without relying on the return of the rectangular sealing ring 3.8, thereby truly achieving the requirement of low drag; Figure 7 It is a disassembly schematic diagram of the nut, the retaining spring and the piston of the present invention, as well as a specific structural schematic diagram of the retaining spring, the nut and the piston.

[0080] The outer gasket 3.3.1 and the anti-rotation gasket 3.3.3 cooperate with the force sensor 3.3.2 through the end face. During the transmission process, the screw 3.6.1 rotates, generating an axial thrust on the screw shaft ring 3.6.2, causing the thrust bearing 3.4 to rotate, and applying the axial thrust to the anti-rotation gasket 3.3.3, thereby generating a positive bearing pressure on the force sensor 3.3.2, and the generated pressure is output through the force sensor 3.3.2; the thrust bearing 3.4 and the anti-rotation gasket 3.3.3 cooperate and rotate on the end face of the anti-rotation gasket 3.3.3. Under the action of the rotational friction force, the anti-rotation gasket 3.3.3 will have a tendency to rotate. The anti-rotation gasket 3.3.3 of the present invention cooperates with the anti-rotation groove 3.3.3.1 arranged on the anti-rotation gasket and the anti-rotation bolt 3.10 arranged on the housing 3.2 to prevent the anti-rotation gasket 3.3.3 from rotating during the transmission process.

[0081] In the prior art, such as Figure 8 As shown, the sleeve is installed on the outside of the screw, and the sleeve and the screw are matched with a very small gap, and the clearance between the nut and the piston below is matched to complete the circumferential positioning. Compared with the ball screw structure, the straight section is too short to form a reliable circumferential positioning; the present invention adjusts the matching size of the piston 3.7 and the nut 3.6.3, and uses the piston 3.7 to position the nut 3.6.3 in the circumferential direction. The reason for using the ball screw assembly 3.6 is that, compared with the existing thread structure ( Figure 8 ) can withstand greater axial forces than ball screws. After using a ball screw, the ball screw can basically fill the piston 3.7, and the nut 3.6.3 has a long straight contact section with the piston 3.7, so the piston 3.7 can be directly used for axial positioning. However, the existing thread structure design has a large gap between the piston and the piston, and it is particularly uneconomical to add a lot of materials for circumferential positioning. Therefore, the thread structure adopts a method of installing a sleeve on the housing, and the circumferential positioning is achieved through the contact between the sleeve and the nut. In summary, the present invention reduces the use of sleeves in the prior art.

[0082] The piston 3.7 is generally in the shape of a hollow cylinder with one side open, and is sleeved on the outside of the ball screw assembly 3.6. The interior of the piston 3.7 and the corresponding position of the convex spherical surface at the bottom edge of the nut 3.6.3 are processed into a concave spherical surface matching the convex spherical surface; the interior of the piston 3.7 is also processed with a retaining ring installation groove 3.7.1 for installing a retaining ring.

[0083] The rectangular sealing ring 3.8 is waterproof and oil-repellent, and is arranged between the housing 3.2 and the piston 3.7 to provide rubber damping to reduce impact noise and knocks.

[0084] The dust cover 3.9 is installed near the bottom of the piston and is designed to be pleated. The pleated design meets the dust protection requirements under all working conditions.

[0085] The friction plate 5 is installed in the brake bracket 4, and further includes an inner friction plate 5.2 and an outer friction plate 5.1. During braking, the inner and outer friction plates move toward each other and clamp the brake disc, thereby generating a vehicle braking torque.

[0086] The present invention adopts 2 spherical compensations (see Fig. 9 ), the first is the contact position between the nut 3.6.3 and the piston 3.7, and the second is the connection position between the screw shaft ring 3.6.2, the screw shaft 3.6.1.1 and the screw inner shaft 3.6.1.2. When designing, the piston 3.7 and the screw 3.6.1 are perpendicular to the friction plate 5, but the caliper bridge back is one-sided, and the caliper will definitely deform when clamping, that is, under loading conditions, the housing cylinder hole and the housing claw (the claw and the friction plate are in contact) are not perpendicular, such as Fig.17 This results in that when the piston 3.7 and the screw 3.6.1 are not perpendicular to the friction plate 5, the screw 3.6.1 will be subjected to a large shear force. At this time, the role of spherical compensation is revealed, and the shear force can be absorbed by slightly rotating the two spherical surfaces, thereby ensuring that the ball screw assembly 3.6 will not fail easily.

[0087] The screw spline 3.6.1.3 of the screw 3.6.1 adopts the form of an external spline, the strength of the external spline is higher than that of the internal spline, and the present invention adopts a special form of external spline, the extension line of the spline force surface passes through the center of the circle (see Fig.10 ), so the direction of the force on the meshing point of the spline is the tangent direction of the circle, and there is no additional force component to reduce the transmission of torque. In theory, this is the most efficient way to transmit torque; or you can choose to make the extension line of the force surface of the screw spline 3.6.1.3 tangent to the circle with a center diameter of 1.5mm of the screw spline 3.6.1.3, such as Fig.10 shown.

[0088] An axial seal is used between the caliper assembly and the gearbox assembly (see Fig.12 ) method. Compared with the commonly used radial seal (see Fig.11 ) has a higher axial space utilization rate and saves one shell machining, which is transferred to the gearbox assembly shell. The gearbox assembly shell is formed by molds, which basically does not increase the cost and is more economical, but the axial sealing method can only be applied to projects with large cylinder diameters. The commonly used radial sealing method integrates the MGU sealing ring groove on the gearbox assembly shell by injection molding; in addition, in the radial sealing method, the height will be higher than the axial sealing due to the limitation of the MGU sealing ring groove on the shell. In radial sealing, machining is required to achieve grooving, and in axial sealing, molds are required to ensure grooving. In the case of mass production, the cost of axial sealing will be more advantageous.

[0089] Fig.13From left to right are the MGU sealing ring installed in the gearbox assembly housing and the structural diagram of the housing, MGU sealing ring and gearbox assembly.

[0090] Fig.15 From left to right are the schematic diagrams of the MGU sealing ring, anti-rotation bolt, anti-rotation gasket, rectangular sealing ring, and dust cover structure.

[0091] Fig.16 From left to right are the top view of the connection between the shell and the bracket and the cross-sectional view along the EE plane.

[0092] The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the present invention, changes and advantages that can be thought of by those skilled in the art are included in the present invention and are protected by the attached claims.

Claims

1. An electromechanical brake, characterized in that: The brake comprises: a drive motor (1), a gear box assembly (2), a caliper assembly (3), a brake bracket (4), and a friction plate (5); The axis of the driving motor (1) is parallel to the axis of the caliper assembly (3), and is used to realize the driving and releasing of the brake; The gearbox assembly (2) includes a gear transmission system, and the drive motor (1) provides the torque required for braking; The caliper assembly (3) is the main structure of the brake, providing housing protection and converting the torque of the gearbox assembly (2) into axial movement; The friction plate (5) is installed in the brake bracket (4), and comprises an inner friction plate (5.2) and an outer friction plate (5.1). During braking, the inner and outer friction plates move towards each other and clamp the brake disc, thereby generating a vehicle braking torque.

2. The brake according to claim 1, characterized in that The gearbox assembly (2) is mounted on the caliper assembly (3) via an MGU screw (6); the caliper assembly (3) is connected to the brake bracket (4) via a flange bolt (7).

3. The brake according to claim 1, characterized in that The caliper assembly comprises a snap ring (3.1), a housing (3.2), a force feedback unit (3.3), a thrust bearing (3.4), a snap spring (3.5), a ball screw assembly (3.6), a piston (3.7), a sealing ring (3.8), a dust cover (3.9), and a stop bolt (3.10); The ball screw assembly (3.6) comprises a screw (3.6.1), a screw shaft ring (3.6.2), and a nut (3.6.3); the screw comprises a screw shaft (3.6.1.1) with a screw spline (3.6.1.3) on the top and a screw inner shaft (3.6.1.2) with threads; The clamping ring (3.1) is assembled together with the inner ring and the screw shaft (3.6.1.1) by interference fit, and is used to prevent the screw spline (3.6.1.3) at the top of the screw shaft from coming out from the matching spline in the gear box; The housing (3.2) is integrally formed, and a housing cylinder hole for accommodating a ball screw assembly (3.6) is provided in the middle thereof; during operation, the positions of the drive motor (1), the gear box assembly (2), and the housing (3.2) remain relatively fixed, and the drive motor (1), the gear box assembly (2), and the housing (3.2) can move relative to the brake bracket (4); a stop hole (3.2.1) is also provided on the housing (3.2) for inserting a stop bolt (3.10).

4. The brake according to claim 3, characterized in that The screw shaft ring (3.6.2) is annular in shape as a whole, and an internal spline (3.6.2.1) is arranged in the middle. The size of the internal spline (3.6.2.1) is larger than that of the screw shaft ( 3.6.1.1) is smaller than the diameter of the inner shaft of the screw (3.6.1.2), and the screw shaft ring (3.6.2) is sleeved on the screw optical axis ( The position where the screw shaft ring (3.6.2) contacts the screw (3.6.1) is processed into a concave spherical surface; the nut (3.6.3) is in the shape of a hollow cylinder that passes through from top to bottom, and is sleeved on the inner shaft of the screw (3.6.1.2), and the outer edge of the bottom is processed into a convex spherical surface, which corresponds to the concave spherical surface processed and set in the piston (3.7); The position on the inner shaft (3.6.1.2) of the screw that intersects with the optical axis (3.6.1.1) of the screw is designed to be a convex spherical surface that matches the concave spherical surface of the screw shaft ring (3.6.2).

5. The brake according to claim 3, characterized in that The relative positions of the screw shaft ring (3.6.2) and the nut (3.6.3) are respectively provided with boss features in the shape of right triangles, namely the shaft ring boss feature (3.6.2.2) and the nut boss feature (3.6.3.1). The two vertical right-angled sides of the shaft ring boss feature (3.6.2.2) and the nut boss feature (3.6.3.1) can ensure that the vertical surfaces of the two are in contact by adjusting the angle of the internal spline (3.6.2.1) of the screw shaft ring.

6. The brake according to claim 3, characterized in that The force feedback unit (3.3) is positioned and installed on the lead screw optical axis (3.6.1.1) with a middle opening, and is clearance-matched with the lead screw optical axis (3.6.1.1), so as to be able to provide real-time feedback of the clamping force to the control system, and the force feedback unit (3.3) does not rotate during the transmission process; the force feedback unit (3.3) comprises an outer gasket (3.3.1), a force sensor (3.3.2), and a rotation-stop gasket (3.3.3); the rotation-stop gasket (3.3.3) is also provided with a rotation-stop groove (3.3.3.1), so that the rotation-stop gasket (3.3.3) can be stopped by inserting and removing a rotation-stop bolt (3.10).

7. The brake according to claim 4, characterized in that A thrust bearing (3.4) is also installed between the force feedback unit (3.3) and the screw shaft ring (3.6.2), and the thrust bearing (3.4) is used to bear the axial thrust generated by the brake during operation and reduce the friction between the screw shaft ring (3.6.2) and the anti-rotation washer (3.3.3); The retaining spring (3.5) is installed between the nut (3.6.3) and the piston (3.7) to fix the nut (3.6.3) and the piston (3.7) together, so that the piston (3.7) and the nut (3.6.3) are relatively fixed, so that the piston (3.7) can be returned through the ball screw assembly (3.6) without relying on the return of the rectangular sealing ring (3.8), thereby achieving the requirement of low drag.

8. The brake according to claim 6, characterized in that The outer gasket (3.3.1) and the anti-rotation gasket (3.3.3) cooperate with the force sensor (3.3.2) through the end faces. During the transmission process, the lead screw (3.6.1) rotates, generating an axial thrust on the lead screw shaft ring (3.6.2), driving the thrust bearing (3.4) to rotate, and applying the axial thrust to the anti-rotation gasket (3.3.3), thereby generating a positive bearing pressure on the force sensor (3.3.2). The generated pressure is transmitted through the force sensor (3.

3. 2) output; the thrust bearing (3.4) and the anti-rotation gasket (3.3.3) cooperate and rotate on the end face of the anti-rotation gasket (3.3.3); under the action of the rotational friction force, the anti-rotation gasket (3.3.3) will have a tendency to rotate, and the anti-rotation gasket (3.3.3) cooperates with the anti-rotation groove (3.3.3.1) provided on the anti-rotation gasket and the anti-rotation bolt (3.10) provided on the housing (3.2) to prevent the anti-rotation gasket (3.3.3) from rotating during the transmission process.

9. The brake according to claim 3, characterized in that The piston (3.7) is generally in the shape of a hollow cylinder with one side open, and is sleeved on the outside of the ball screw assembly (3.6). The interior of the piston (3.7) and the corresponding position of the convex spherical surface at the bottom edge of the nut (3.6.3) are processed into a concave spherical surface matching the convex spherical surface. The rectangular sealing ring (3.8) is arranged between the housing (3.2) and the piston (3.7) to provide rubber damping and reduce impact noise and knocks; The dust cover (3.9) is installed at a position close to the bottom of the piston (3.7) and is designed to be pleated. The pleated design satisfies the dust prevention requirements under all working conditions.

10. The brake according to claim 3, characterized in that The extension line of the force-bearing surface of the screw spline (3.6.1.3) passes through the center of the circle, or the extension line of the force-bearing surface is within the φ1.5mm area of ​​the center of the circle.

11. A braking method using the brake according to any one of claims 1 to 10, characterized in that: The steps include: Step 1: The driving motor (1) drives the gearbox assembly (2) to amplify the torque; Step 2: The gearbox assembly (2) drives the ball screw assembly (3.6) to rotate through the meshing splines; Step 3: The ball screw assembly (3.6) converts the torque of the gearbox assembly (2) into an axial thrust along the cylinder bore of the housing and generates a positive pressure on the piston (3.7); Step 4: The piston (3.7) is displaced in the direction of the friction plate (5); Step 5: The displacement and force of the piston (3.7) continue to increase under the action of the gearbox assembly (2), and the friction plate (5) presses the brake disc to generate the pressure required for braking, thereby achieving the braking function.

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