High-thrust electric brake actuator with shutdown braking capacity

Abstract

The invention relates to the technical field of airplane wheel braking, in particular to a high-thrust electric brake actuator with stopping braking capacity, which comprises a shell assembly, a ball screw assembly, a motor and a brake, the shell assembly comprises an upper shell and a lower shell, a force sensor serves as the upper shell, the lower shell comprises a driving cavity and an actuating cavity, and the driving cavity is communicated with the actuating cavity. The driving cavity is communicated with the actuating cavity; the ball screw assembly is arranged in the actuating cavity of the lower shell, and the output end of the ball screw assembly serves as the output end of an actuator and penetrates out of the actuating cavity. The motor is arranged in the driving cavity, the output end of the motor is in transmission connection with the input end of the ball screw assembly through the reduction gear assembly, and the reduction gear assembly is in three-stage speed reduction. The brake is used for braking the input end gear of the reduction gear assembly. The device overcomes the problems that an electric brake actuator is high in installation precision requirement, complex in structure, low in system integration level, insufficient in brake acting force, inconvenient to install and maintain and incapable of stopping for braking.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft wheel brakes, and particularly relates to a high-thrust electric brake actuator with parking brake capability. Background Art

[0002] With the increasingly strong development demand of more-electric / all-electric aircraft, the requirements for braking technology are also getting higher and higher. The trend of aircraft braking method is from hydraulic control to electric control. As a new technology, electric braking uses an electric brake actuator as the braking actuator. An electric brake actuator generally consists of components such as a brushless DC motor, a reduction gear, a ball screw assembly, a force sensor, and bearings.

[0003] Currently, hydraulic brake devices are widely used in aircraft wheel brake devices. Although they can meet the basic braking functions of the aircraft, they are extremely dependent on the hydraulic system in the aircraft to provide a hydraulic source. At the same time, a variety of hydraulic accessories and complex pipelines need to be laid to achieve the braking function, which is difficult to meet the development requirements of more-electric / all-electric aircraft; secondly, there is a potential safety hazard of fire caused by hydraulic oil leakage.

[0004] In the prior art, an electromechanical actuator for unmanned aircraft braking is proposed. It is driven by bevel gears, which requires extremely high meshing accuracy of the gears, and at the same time increases the processing difficulty and cost of the bevel gears; in addition, the proposed electromechanical actuator can only provide a braking force of 1800N and can only be applied to small unmanned aircraft and cannot meet the braking requirements of large-tonnage unmanned aircraft. The prior art also proposes an actuator for an aircraft electric brake device, whose reduction ratio is 53:1 and can provide a relatively large braking force, but the actuator structure is relatively complex and not convenient for installation and maintenance. The force sensor adopts a split design of the body and the conditioning module. When assembling, the cable between the two needs to be cut and re-welded, which has a great impact on the signal transmission and service life of the force sensor; there is no motor long-time braking device. When the aircraft brakes on the takeoff line, the motor needs to be continuously powered to brake the aircraft, which will cause the motor to be blocked for a long time and energy waste. And an electric brake actuator of the prior art includes a motor, a brake, a gear assembly, a screw assembly, and a signal conditioning module. This electric brake actuator combines electromagnetic drive and piezoelectric drive. First, the screw assembly is driven by an electromagnetic motor to eliminate the braking clearance, and there is no braking force; then the motor shaft is locked by the brake, and then piezoelectric drive is used to provide the braking force, but the elongation is only 0-0.05mm, and the maximum braking force that can be provided is only 3000N. It does not consider that the deformation of the brake device during aircraft braking is above the mm level. This electric brake actuator is difficult to ensure the braking force acting on the brake disc and is difficult to perform anti-skid control.

[0005] In summary, the electromechanical actuator for UAV braking proposed in the prior art is driven by bevel gears, which requires extremely high gear meshing accuracy and increases the processing difficulty and cost of the bevel gears. In addition, the electromechanical actuator proposed can only provide 1800N braking force and can only be used in small UAVs, and cannot meet the braking requirements of large UAVs weighing 30 tons.

[0006] Therefore, it is necessary to provide a high-thrust electric brake actuator with parking brake capability to solve the above problems. Summary of the Invention

[0007] In order to solve the problem that bevel gears are used for transmission in the prior art, the meshing accuracy of the gears is extremely high, and the processing difficulty and cost of the bevel gears will be increased; and the existing electromechanical actuator can only provide 1800N braking force, which can only be used in small drones and cannot meet the braking requirements of large drones above 30 tons. The present invention provides a high-thrust electric brake actuator with parking brake capability. By highly integrating the force sensor with the actuator upper shell, the overall structure is divided into two parts: a purely mechanical structural component and a purely electrical structural component. The structure is simple and maintenance is convenient; the reduction gear assembly performs high reduction ratio transmission, so that the rated braking force can reach 40,000N, and the brake is coordinated with the reduction gear to achieve parking braking to solve the existing problem.

[0008] The present invention provides a high-thrust electric brake actuator with parking brake capability, which adopts the following technical solutions, including: A housing assembly comprising an upper housing and a lower housing, wherein the force sensor serves as the upper housing, and the lower housing comprises a drive cavity and an actuation cavity, wherein the drive cavity and the actuation cavity are connected, and the force sensor is used to directly contact and measure the reaction force of the ball screw assembly when it is in operation; The ball screw assembly is disposed in the actuating cavity of the lower housing, and its output end serves as an actuator output end and passes through the actuating cavity; The motor is arranged in the driving cavity, and the output end of the motor is connected to the input end of the ball screw assembly through a reduction gear assembly, wherein the reduction gear assembly is a three-stage reduction gear assembly; and a brake for braking the input end gear of the reduction gear assembly.

[0009] Preferably, the reduction gear assembly comprises: A first double gear is rotatably disposed in the drive cavity, wherein the large gear on the first gear meshes with the output gear provided on the output shaft of the motor, and the large gear on the first gear is provided with a stop structure for cooperating with the output end of the brake; And a second duplex gear is rotatably arranged in the driving cavity, the large gear on the second duplex gear is meshed with the small gear of the first duplex gear, and the small gear on the second duplex gear is transmission-connected to the input end of the ball screw assembly.

[0010] Preferably, the ball screw assembly includes: A ball screw having a groove formed in an end face along its axial direction; A connecting column coaxially disposed at an end of the ball screw away from the groove and rotatably connected to the upper housing; A transmission gear sleeved and fixed on the connecting column, wherein the transmission gear meshes with the pinion of the second double gear; A ball nut having a long cylinder structure, threadedly connected to the ball screw, axially slidably disposed in the actuating cavity along the ball screw, and having an oil retaining sleeve provided at one end after protruding from the actuating cavity, and a sealing cavity is formed by the oil retaining sleeve and the groove of the ball screw; A heat insulation pad installed at the end of the ball nut through a snap ring; And a sealing assembly disposed on the inner wall of the cavity in contact with the outer ring of the ball nut.

[0011] Preferably, a guide sleeve is sleeved and fixed in the actuating cavity. The ball nut of the ball screw assembly is axially slidably disposed in the guide sleeve along the length direction of the guide sleeve. A limit bushing is sleeved on the ball nut at the end protruding from the guide sleeve. The outer ring of the limit bushing is threadedly connected to the port of the actuating cavity, and a support ring is provided on the inner ring of the bushing; Wherein, the sealing assembly is disposed in a sealing groove formed in the inner ring of the bushing.

[0012] Preferably, the sealing assembly includes: A sealing ring and a dust-proof ring, wherein the sealing ring and the dust-proof ring are installed in a sealing groove formed in the inner ring of the bushing.

[0013] Preferably, the heat insulation pad has an end cover structure, its inner ring is connected to the end of the ball nut through a snap ring, and the heat insulation pad is made of titanium alloy material.

[0014] Preferably, a bearing spacer is sleeved on the connecting column, and a bearing washer is sleeved and fixed on the bearing spacer. The bearing washer is located between the inner wall of the upper housing and the transmission gear. A thrust needle roller bearing is provided between the bearing washer and the transmission gear.

[0015] Preferably, the stopping structure is a plurality of stopping jacks formed in the end face of the large gear of the first double gear. The brake is a pin brake, and the stopping jacks are used to cooperate with the pins of the pin brake.

[0016] Preferably, the parameters of the large gear of the first double gear are: normal module 0.75, number of teeth 81, tooth profile angle 20°, and radial modification coefficient -0.4; the parameters of the small gear of the first double gear are: normal module 0.9, number of teeth 16, tooth profile angle 20°, and radial modification coefficient +0.4; the parameters of the large gear of the second double gear are: normal module 0.9, number of teeth 49, tooth profile angle 20°, and radial modification coefficient -0.4; the parameters of the small gear of the second double gear are: normal module 1.25, number of teeth 19, tooth profile angle 20°, and radial modification coefficient +0.4.

[0017] Preferably, the heat insulation pad is made of titanium alloy material.

[0018] The beneficial effects of the present invention are as follows: Through the reduction gear assembly and ball screw assembly in the present invention, they are the actuating mechanisms of the electric brake actuator. The input torque of the motor is amplified by the reduction gear assembly and then converted into a linear braking force output. The braking force acts on the brake disc to push and squeeze between the moving disc and the static disc to generate a braking torque, achieving the purpose of braking. On the premise of ensuring stiffness and load-bearing capacity, the reduction gear set adopts a three-stage reduction design, and a ball screw assembly with higher transmission efficiency is selected to replace the roller screw assembly. Through reasonable layout, the overall structure of the brake actuator is ensured to be compact and with a large thrust. Secondly, in the present invention, the force sensor is used as the upper housing, realizing high integration, increasing the overall rigidity of the force sensor and the force feedback accuracy, realizing force closed-loop control, and reducing the assembly difficulty of the electric brake actuator. The selected brake can ensure that the braking force of the aircraft is maintained at the target value position during parking braking and takeoff line braking, realizing the parking braking function. The present invention overcomes the problems of high installation accuracy requirements, complex structure, low system integration, insufficient braking force, inconvenient installation and maintenance, and inability to park brake of the electric brake actuator. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 It is a schematic structural diagram of the electric brake actuator of the present invention; Figure 2 It is a top view of the electric brake actuator; Figure 3 It is a sectional view of the lower housing of the actuator; Figure 4 It is a bottom view of the lower housing of the actuator; Figure 5 is a sectional view of the force sensor; Figure 6 is an isometric view of the force sensor; Figure 7 is an isometric view of the brushless DC motor; Figure 8 is a sectional view of the transmission assembly; Figure 9 is a top view of the first double gear; Figure 10 is a top view of the guide sleeve; Figure 11 is an isometric view of the guide sleeve; Figure 12 is a sectional view of the bushing; Figure 13 is a sectional view of the oil baffle sleeve; Figure 14 is a sectional view of the heat insulation pad; Figure 15 is an isometric view of the ball screw; Figure 16 is an isometric view of the ball nut; Figure 17 is a sectional view of the plug - type brake in the braking state; Figure 18 is a sectional view of the plug - type brake in the released state.

[0021] In the figure: 1. Lower housing; 2. Force sensor; 3. Motor; 4. Brake; 5. Reduction gear assembly; 6. Ball screw assembly; 7. Thrust needle roller bearing; 8. Dust plug; 9. Bearing spacer ring; 10. Bearing washer; 11. Guide sleeve; 12. Support ring; 13. Limit bushing; 14. Sealing ring; 15. Oil baffle sleeve; 16. Heat insulation pad; 17. Snap ring; 18. Dust seal; 19. Gear shaft; 20. Socket assembly; 21. First double gear; 22. Second double gear; 23. Ball screw; 24. Ball nut. Specific embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] An embodiment of a large - thrust electric brake actuator with a stop - brake function according to the present invention, as Figure 1As shown, it includes: a housing assembly, a ball screw assembly 6, a motor 3 and a brake 4. The housing assembly includes: an upper housing and a lower housing 1, and the upper housing and the lower housing 1 are connected by screws, wherein, as shown in FIG. Figure 5 and Figure 6 As shown, the force sensor 2 serves as the upper shell, and a signal conditioning module is integrated on the upper shell. The force sensor 2 is used to directly contact and measure the reaction force of the ball screw assembly when it is working; Figure 3 and Figure 4 As shown, the lower shell 1 includes a driving cavity and an actuating cavity, and the driving cavity and the actuating cavity are connected; the ball screw assembly 6 is arranged in the actuating cavity of the lower shell 1, and the output end of the ball screw assembly 6 passes through the actuating cavity as the output end of the actuator; the motor 3 is arranged in the driving cavity, which is fixed to the upper shell by screws, and the output end of the motor 3 is connected through the reduction gear assembly 5 and the input end of the ball screw assembly 6, wherein the reduction gear assembly 5 is a three-stage reduction with a reduction ratio of 61:1, which can effectively amplify the output torque of the motor 3 and convert it into a linear force output through the ball screw assembly 6, thereby achieving a small volume, small torque and large thrust effect; the brake 4 is used to brake the input end gear of the reduction gear assembly.

[0024] It should be noted that a signal conditioning module is integrated on the upper shell, and the signal conditioning module is used to convert the millivolt voltage signal into a milliampere current signal, so as to avoid electromagnetic interference of the high-voltage signal on the aircraft on the feedback signal of the force sensor, and improve the accuracy and anti-interference performance of the force sensor. The lower shell 1 adopts precision casting technology, and the material is cast stainless steel ZG0Cr17Ni4Cu3Nb. After casting, the key dimensions are machined, which not only reduces the production cost but also improves the processing efficiency. A sealing ring groove is designed on the upper end face of the lower shell 1 to achieve sealing between the upper shell and the lower shell 1, and prevent impurities such as rain, sand and dust from entering the brake actuator and causing the reduction gear assembly 5 to get stuck. The lower shell 1 is designed with positioning grooves for installing the motor shaft of the motor 3, the reduction gear assembly 5 and the ball screw assembly 6. Each positioning groove and the reduction gear assembly 5 and the gear shaft 19 are matched with a small clearance, which can effectively prevent the force deformation during assembly from affecting the transmission accuracy and life, and greatly reduces the difficulty of assembly; such as Figure 7 As shown, the motor 3 adopts a brushless DC motor. The motor 3 adopts existing mature technology and has a rated torque of 0.7N·m. The output gear parameters on the output shaft of the motor 3 are: normal module 0.75, number of teeth 13, tooth angle 20°, radial displacement coefficient 0.4. The brushless DC motor is fitted with a small clearance in the motor mounting hole in the upper housing and is fixed by five bolts. The motor 3 is designed with a wire output hole and a socket component connection hole; Figure 2As shown, the lead wires of the force sensor 2 and the lead wires of the pin brake are gathered through the wire threading holes in the upper housing and then led out. Together with the lead wires of the brushless DC motor, they are all connected to the socket assembly 20 provided at the top of the upper housing through the output wire holes of the brushless DC motor housing, ensuring that all lead wires are inside the electro-brake actuator and are reliably positioned, significantly reducing the risk of cable exposure and damage.

[0025] Exemplarily, as Figure 8 shown, in a specific embodiment, the reduction gear assembly 5 includes: a first double gear 21 and a second double gear 22. As Figure 9 shown, the first double gear 21 is rotatably arranged in the drive cavity through the gear shaft thereon. The large gear on the first double gear 21 meshes with the output gear provided on the output shaft of the motor 3, and a stop structure for cooperating with the output end of the brake 4 is provided on the large gear thereon; the second double gear 22 is rotatably arranged in the drive cavity through the gear shaft 19 thereon. The large gear on the second double gear 22 meshes with the small gear of the first double gear 21, and the small gear on the second double gear 22 is drivingly connected to the input end of the ball screw assembly.

[0026] Among them, in a specific embodiment, the parameters of the large gear of the first double gear 21 are: normal module 0.75, number of teeth 81, tooth profile angle 20°, and radial modification coefficient -0.4; the gear parameters of the first double gear 21 are: normal module 0.9, number of teeth 16, tooth profile angle 20°, and radial modification coefficient +0.4; the parameters of the large gear of the second double gear 22 are: normal module 0.9, number of teeth 49, tooth profile angle 20°, and radial modification coefficient -0.4; the parameters of the small gear of the second double gear 22 are: normal module 1.25, number of teeth 19, tooth profile angle 20°, and radial modification coefficient +0.4. In a specific embodiment, the stop structure is a plurality of stop jacks opened on the end face of the large gear of the first double gear 21. Among them, the brake 4 is a pin brake, and the stop jacks are used to cooperate with the pins of the pin brake. Among them, the brake 4 is in small clearance fit with the brake mounting hole in the upper housing and is fixed by two bolts. It should be noted that as Figure 17 and Figure 18 shown, the pin brake is a prior art. By inputting positive and negative pulse currents, the extension and contraction of the pin are realized. After the pin extends and is inserted into the stop jacks on the large gear of the first double gear 21, when the electro-brake actuator is powered off, the braking torque can continue to be maintained without long-term power-on and no heat is generated, and the stop brake function can be realized; after the pin retracts, the transmission assembly can rotate freely.

[0027] Exemplarily, in a specific embodiment, the ball screw assembly 6 includes: a ball screw 23, a connecting column, a transmission gear, a ball nut 24, a heat insulation pad 16, and a sealing assembly; asFigure 15 As shown, a groove is formed on the axial end surface of the ball screw 23; a connecting post is coaxially connected to the end of the ball screw 23 away from the groove, and the connecting post is rotatably connected to the upper housing; a transmission gear is fixed to the connecting post, wherein the transmission gear is meshed with the pinion of the second double gear 22; Figure 16 As shown, the ball nut 24 is a long cylindrical structure, which is connected to the ball screw 23 by a thread, and is set in the actuating cavity along the axial sliding of the ball screw 23, and an oil retaining sleeve 15 is set after one end of the ball nut 24 extends out of the actuating cavity, as shown in FIG. Figure 1 and Figure 13 As shown, the groove of the oil retaining sleeve 15 and the ball screw 23 forms a sealed cavity. The oil retaining sleeve 1 is used to prevent the grease in the raceway from being thrown out during the rotational motion, and the oil retaining sleeve 15 is interference fit with the inner cavity of the ball nut 24; the heat insulation pad 16 is installed at the end of the ball nut 24 through the spring retaining ring 17; the sealing assembly is arranged on the inner wall of the cavity in contact with the outer ring of the ball nut 24. It should be noted that, as shown in FIG. Figure 14 As shown, the thermal insulation pad 16 is an end cover structure, and its inner ring is connected to the end of the ball nut 24 through a spring retaining ring 17. The thermal insulation pad 16 is used to directly contact the brake disc and transmit the thrust of the ball nut 24 to the brake disc. Therefore, the thermal insulation pad 16 is made of titanium alloy material with excellent thermal strength performance.

[0028] Among them, such as Figure 1 、 Figure 10 and Figure 11 As shown in FIG. 1 , in a specific embodiment, a guide sleeve 11 is fixedly mounted in the actuating cavity, wherein the ball nut 24 of the ball screw assembly 6 is slidably arranged in the guide sleeve 11 along the length direction of the guide sleeve 11, and a limiting bushing 13 is mounted on the end of the ball nut 24 extending out of the guide sleeve 11. Figure 1 and Figure 12 As shown, the outer ring of the limiting bushing 13 is threadedly connected to the port of the actuating cavity, and the inner ring of the bushing 13 is provided with a support ring 12, wherein the sealing assembly is arranged in the sealing groove opened in the inner ring of the bushing 13, and the sealing assembly includes: a sealing ring 14 and a dust ring 18, wherein the sealing ring 14 and the dust ring 18 are installed in the sealing groove opened in the inner ring of the bushing 13. Specifically, two grooves are designed on the inner end face of the bushing 13, one for installing the support ring 12, and the other for installing the sealing ring 14 and the dust ring 18 of the sealing assembly; the support ring 12 is used to prevent radial runout of the ball nut; the dust ring 18 relies on the compression amount of the sealing ring 14 to always maintain good sealing to the ball nut 24 to prevent dust from entering.

[0029] Among them, in a specific embodiment, the connecting column is connected to the mounting hole provided in the upper housing through a bearing, and a dust plug 8 is provided at one end of the connecting column extending out of the bearing. The dust plug 8 is used to seal the exposed ball screw extension shaft and the bearing to prevent impurities from entering. At the same time, when it is necessary to detect the state of the transmission component in the power-off state, the dust plug 8 here can be taken out, and the external hexagonal wrench can be used to manually detect the rotational flexibility of the transmission component. A bearing spacer 9 is sleeved on the connecting column, and a bearing washer 10 is fixedly sleeved on the bearing spacer 9. The bearing washer 10 is located between the inner wall of the upper housing and the transmission gear. Among them, a thrust needle bearing 7 is provided between the bearing washer 10 and the transmission gear. The bearing washer is used to transmit the axial force borne by the thrust needle shaft 7 to the force-receiving surface of the force sensor 2. The thrust ball bearing 7 is a standard part with a thickness of only 5 mm and can bear a static load of 70,800 N. The bearing washer 10 is designed with an upper end surface smaller than the lower end surface, and the smaller contact area is beneficial to ensuring the force-receiving accuracy of the force sensor 2.

[0030] It should be noted that in this embodiment, in order to ensure that the electric brake actuator meets the requirements of small volume and large thrust, the ball screw 23 and the connecting column are of an integrated umbrella-shaped structure. The outermost ring of the umbrella-shaped structure is provided with a transmission gear. A positioning boss is designed at the top of the ball screw umbrella for installing the thrust needle bearing 7; two anti-rotation bosses are designed at the bottom of the ball screw umbrella; two anti-rotation bosses are also designed on the upper end surface of the ball nut 24 for meshing with the anti-rotation bosses on the ball screw 23 to achieve the anti-reverse-top effect; the outer circumferential surface of the ball nut 24 is of a two-piece structure, including a cylindrical section and a quasi-hexagonal prism section; the outer circumferential surface of the ball nut 24 is in sliding fit with the inner hole of the guide sleeve 11; the guide sleeve 11 has a mounting plate, and mounting holes are distributed on the mounting plate of the guide sleeve 11 and are tightened with the actuator housing by screws; the outer circumferential surface of the guide sleeve 11 is a cylindrical surface, and the inner circumferential surface is of a quasi-hexagonal shape; the outer diameter of the guide sleeve 11 is slightly smaller than the inner diameter of the actuating cavity of the lower housing 1, and the two are in clearance fit.

[0031] Working principle During use, the control motor 3 operates. The output gear on the output shaft of the motor 3 meshes with the large gear of the first double gear 21 of the reduction gear assembly 5 to drive the first double gear 21 to rotate. The small gear of the first double gear 21 meshes internally with the large gear of the second double gear 22 to drive the second double gear 22 to rotate. The small gear of the second double gear 22 meshes with the transmission gear on the ball screw assembly 6 to drive the ball screw 23 of the ball screw assembly 6 to rotate. As the ball screw 23 rotates, the ball nut 24 thereon linearly extends or contracts under the guiding action of the guide sleeve 11, so that the heat insulation pad 6 at the end of the ball nut 24 directly contacts the brake disc to generate a braking driving force. The braking driving force pushes the moving disc and the static disc to be squeezed to generate a braking torque, achieving the purpose of braking. During shutdown braking, only the brake 4 needs to be given positive and negative pulse currents to realize the extension and contraction of the pin. After the pin extends, it is inserted into the stop jack on the large gear of the first double gear 21. At this time, after the electro-brake actuator is powered off, the braking torque can continue to be maintained, without long-term power-on and no heat generation, and the shutdown braking function can be realized; after the pin retracts, the transmission component can rotate freely.

[0032] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A large-thrust electric brake actuator with parking brake ability, characterized in that, include: A housing assembly comprising: an upper housing and a lower housing (1), wherein a force sensor (2) serves as the upper housing, and the lower housing (1) comprises a driving cavity and an actuating cavity, and the driving cavity and the actuating cavity are connected; wherein the force sensor (2) is used for directly contacting and measuring the reaction force of the ball screw assembly when it is working. A ball screw assembly (6) is disposed in the actuating cavity of the lower housing (1), and its output end serves as an actuator output end and passes through the actuating cavity; A motor (3) is arranged in the drive cavity, and its output end is connected to the input end of the ball screw assembly (6) through a reduction gear assembly (5), wherein the reduction gear assembly (5) is a three-stage reduction; and a brake (4) for braking the input end gear of the reduction gear assembly.

2. The large-thrust electric brake actuator with shutdown braking ability according to claim 1, characterized in that The reduction gear assembly (5) comprises: A first double gear (21) is rotatably arranged in the drive cavity, wherein the large gear on the first gear is engaged with the output gear provided on the output shaft of the motor (3), and the large gear on the first gear is provided with a stop structure for cooperating with the output end of the brake (4); and a second duplex gear (22) rotatably disposed in the drive cavity, wherein the large gear on the second duplex gear is meshed with the small gear of the first duplex gear (21), and the small gear on the second duplex gear is transmission-connected to the input end of the ball screw assembly.

3. The large-thrust electric brake actuator with shutdown braking ability according to claim 2, characterized in that, The ball screw assembly (6) comprises: The ball screw (23) has a groove formed on its axial end surface; A connecting column, which is coaxially arranged at the end of the ball screw (23) away from the groove and is rotatably connected to the upper shell; A transmission gear is mounted on the connecting column, wherein the transmission gear is meshed with the pinion of the second double gear (22); The ball nut (24) is a long cylindrical structure, threadedly connected to the ball screw (23), and is arranged in the actuating cavity to slide along the axial direction of the ball screw (23). One end of the ball nut extends out of the actuating cavity and is provided with an oil retaining sleeve (15). The oil retaining sleeve (15) and the groove of the ball screw (23) form a sealed cavity. A heat insulating pad (6) mounted on the end of the ball nut (24) via a spring collar (17); and a sealing assembly, which is arranged on the inner wall of the cavity in contact with the outer ring of the ball nut (24).

4. The large-thrust electric brake actuator with parking brake ability according to claim 3, characterized in that, A guide sleeve (11) is fixedly mounted in the actuating cavity, wherein a ball nut (24) of the ball screw assembly (6) is slidably arranged in the guide sleeve (11) along the length direction of the guide sleeve (11), and a limiting bushing (13) is sleeved on the end of the ball nut (24) extending out of the guide sleeve (11), the outer ring of the limiting bushing (13) is threadedly connected to the port of the actuating cavity, and the inner ring of the bushing (13) is provided with a support ring (12); The sealing component is arranged in a sealing groove provided in the inner ring of the bushing (13).

5. The large-thrust electric brake actuator with parking brake ability according to claim 4, characterized in that The sealing assembly includes: A sealing ring (14) and a dust ring (18), wherein the sealing ring (14) and the dust ring (18) are installed in a sealing groove provided in the inner ring of the bushing (13).

6. The large-thrust electric brake actuator with parking brake ability according to claim 3, characterized in that, The thermal insulation pad (16) is an end cover structure, the inner ring of which is connected to the end of the ball nut (24) through a spring clamp (17), and the thermal insulation pad (16) is made of titanium alloy material.

7. The large-thrust electric brake actuator with parking brake ability according to claim 3, wherein, A bearing washer (9) is sleeved on the connecting column, and a bearing gasket (10) is fixedly sleeved on the bearing washer (9). The bearing gasket (10) is located between the inner wall of the upper housing and the transmission gear. Among them, a thrust needle roller bearing (7) is arranged between the bearing gasket (10) and the transmission gear.

8. The large-thrust electric brake actuator with a parking brake function according to claim 2, characterized in that The stopping structure is a plurality of stopping jacks opened on the large gear end face of the first double gear (21). Among them, the brake (4) is a pin brake, and the stopping jacks are used to cooperate with the pins of the pin brake.

9. The large-thrust electric brake actuator with parking brake ability according to claim 2, characterized in that The parameters of the large gear of the first double gear (21) are: normal module 0.75, number of teeth 81, tooth profile angle 20°, and radial modification coefficient -0.4; the gear parameters of the first double gear (21) are: normal module 0.9, number of teeth 16, tooth profile angle 20°, and radial modification coefficient +0.4; the parameters of the large gear of the second double gear (22) are: normal module 0.9, number of teeth 49, tooth profile angle 20°, and radial modification coefficient -0.4; the parameters of the small gear of the second double gear (22) are: normal module 1.25, number of teeth 19, tooth profile angle 20°, and radial modification coefficient +0.

4.

10. A large-thrust electric brake actuator with parking brake capability according to claim 1, characterized in that, The heat insulation pad (16) is made of titanium alloy material.

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