Electric brake actuator for small unmanned aerial vehicle

Abstract

The invention relates to the technical field of electric brakes, in particular to an electric brake actuator for a small unmanned aerial vehicle, the electric brake actuator comprises a shell, a motor assembly and a force sensor, one end of the shell is open, a ball screw assembly is arranged in the shell, and the output end of the ball screw assembly serves as the output end of the electric brake actuator and penetrates out of the shell; the motor assembly is arranged in the shell, the shell serves as a shell of the motor assembly, and the output end of the shell is in transmission connection with the input end of the driving ball screw assembly and used for driving the output end of the ball screw assembly to stretch out and draw back. The force sensor is arranged at the port of the shell as a cover body and is used for detecting the reaction force generated by the ball screw assembly. According to the device, the size of the actuator is reduced, light weight is achieved, meanwhile, cost is reduced, and low cost is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric brakes, and in particular to an electric brake actuator for a small unmanned aerial vehicle. Background Art

[0002] Electric brakes for small drones have been widely used in recent years. These brakes, which use electromechanical actuators as brake actuators, are an integral part of modern aircraft braking systems, and their performance directly impacts the aircraft's braking effectiveness and safety. Electromechanical actuators typically consist of a motor, force sensor, reduction gears, and a ball screw.

[0003] Traditional electric brake actuators for small drones typically consist of an actuator housing (divided into upper, middle, and lower housings), a motor, a force sensor, a reduction gear set, a ball screw assembly, and bearings. The force sensor and motor are separate LRUs, requiring welding during assembly. This results in a long assembly cycle, large size, high weight, complex structure, and high manufacturing costs. Therefore, traditional electric brake actuators do not meet the requirements of modern small drones for small size, low cost, and lightweight electric brake actuators.

[0004] Therefore, it is necessary to provide an electric brake actuator for a small UAV to solve the above problems. Summary of the Invention

[0005] The present invention provides an electric brake actuator for a small unmanned aerial vehicle to solve the existing problems.

[0006] The electric brake actuator for a small UAV of the present invention adopts the following technical solution, including: A housing having an open end and a ball screw assembly disposed therein, wherein an output end of the ball screw assembly serves as an output end of the electric brake actuator and extends out of the housing; The motor assembly is disposed in the housing, and the housing serves as the outer shell of the motor assembly. The output end of the motor assembly is transmission-connected to the input end of the ball screw assembly, and is used to drive the extension and retraction of the output end of the ball screw assembly. and a force sensor, which serves as a cover and is disposed at a port of the housing and is used to detect a reaction force generated by the ball screw assembly.

[0007] Preferably, the shell is divided into two cavities by a partition, wherein the motor assembly is installed in one cavity and the ball screw assembly is installed in the other cavity, and a connecting port is provided on the partition of the two cavities close to the shell port side.

[0008] Preferably, the motor assembly comprises: A rotating shaft is rotatably disposed in the cavity of the housing, wherein the rotating shaft is connected to the screw of the gear transmission assembly and the ball screw assembly through a transmission connection; a rotor disposed on the rotating shaft; A magnet, which is arranged on the outer periphery of the rotor; And a stator, which is arranged on the wall surface of the cavity of the housing and forms an annular gap with the outer periphery of the rotor.

[0009] Preferably, the gear transmission assembly includes: A gear shaft, which is arranged between the housing of the force sensor and the partition plate in the communication port. Among them, the gear shaft is parallel to the rotating shaft; And a double gear, which is rotatably connected to the gear shaft through a first deep groove ball bearing. Among them, one gear of the double gear meshes with the teeth arranged at the end of the rotating shaft; the other gear of the double gear is in transmission connection with the input end of the ball screw assembly.

[0010] Preferably, the ball screw assembly includes: A ball screw, on the end face along its axis, a groove is opened; A connecting column, which is coaxially arranged at the end of the ball screw and is rotatably connected to the housing of the force sensor; A transmission gear, which is sleeved and fixed on the connecting column, and the transmission gear meshes with the gear of the double gear; A ball nut, which is of a long cylinder structure and is threadedly connected to the ball screw. A rear end portion of the ball nut extending out of the cavity of the housing is internally provided with an oil retaining sleeve. The end portion where the oil retaining sleeve is arranged is sealed through a heat insulation pad, and a sealing cavity is formed between the oil retaining sleeve and the groove; And a sealing assembly, which is arranged on the inner wall of the cavity in contact with the outer ring of the ball nut.

[0011] Preferably, the double gear includes a large gear and a small gear. Among them, the large gear meshes with the teeth on the rotating shaft, and the small gear meshes with the transmission gear on the ball screw.

[0012] Preferably, the sealing assembly includes: a sealing ring and a dust-proof ring. Among them, the sealing ring and the dust-proof ring are installed in a first installation groove opened on the inner wall of the cavity in contact with the outer ring of the ball nut.

[0013] Preferably, a support ring is further included, which is arranged in a second installation groove opened on the inner wall of the cavity in contact with the outer ring of the ball nut.

[0014] Preferably, the connecting column is rotatably connected to a groove arranged on the side of the housing of the force sensor facing the inside of the housing through a second bearing. Among them, a bearing snap ring is further arranged on the connecting column facing the housing of the force sensor, and a bearing spacer ring is further arranged on the connecting column facing the inside of the housing.

[0015] Preferably, the transmission gear is arranged on the connecting column between the second bearing and the end of the ball screw, and an outer ring of the bearing spacer ring is sleeved and fixed with a bearing washer, and a thrust needle roller bearing is arranged between the bearing washer and the transmission gear.

[0016] The beneficial effects of the present invention are: 1. This invention integrates the force sensor with the housing cover, meaning the outer shell of the force sensor directly serves as the cover for the housing's open end. Furthermore, the motor assembly is located within the housing, which also serves as the outer shell for the motor assembly. Compared to traditional electric brake actuators, this reduces the size of the force sensor and motor, saving space and reducing costs. This means that while reducing the actuator's size, this invention also reduces manufacturing costs.

[0017] 2. The ball screw and ball nut of the ball screw assembly of the present invention are both designed with limit steps, which can ensure the relative position between the ball screw and the ball nut during operation, thereby improving reliability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the overall structure of an embodiment of an electric brake actuator for a small UAV of the present invention; Figure 2 This is a diagram showing a state where the output end of an electric brake actuator for a small UAV of the present invention is extended; Figure 3 Schematic diagram of the structure of the force sensor in an embodiment of the present invention.

[0020] In the figure: 1. Force sensor; 2. Housing; 3. Motor assembly; 4. Gear shaft; 5. Duplex gear; 6. First deep groove ball bearing; 7. Ball screw; 8. Thrust needle roller bearing; 9. Bearing washer; 10. Bearing spacer; 11. Bearing retaining ring; 12. Second deep groove ball bearing; 13. Ball nut; 14. Oil deflector sleeve; 15. Support guide ring; 16. Sealing ring; 17. Dust ring; 18. Thermal insulation pad; 19. Thermal insulation pad retaining ring. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] An embodiment of an electric brake actuator for a small drone of the present invention is as followsFigure 1 As shown in the figure, it includes: a housing 2, a motor assembly 3, and a force sensor 1. One end of the housing 2 is open, and a ball screw assembly is arranged inside the housing 2. Wherein, the output end of the ball screw assembly penetrates through the housing 2 as the output end of the electric brake actuator; the motor assembly 3 is arranged inside the housing 2, that is, the housing 2 is used as the outer shell of the motor assembly 3. The output end of the motor assembly 3 is in transmission connection with the input end of the driving ball screw assembly, and is used to drive the telescopic movement of the output end of the ball screw assembly; the force sensor 1 is arranged at the port of the housing 2 as a cover body, and is used to detect the reaction force generated by the ball screw assembly.

[0023] It should be noted that the force sensor 1 is connected to the port of the housing 2 through bolts. The signal wire of the force sensor 1 passes through the signal wire hole on the housing 2 and is connected to the socket of the actuator, and then is connected to the system control unit.

[0024] Exemplarily, in one embodiment, the housing 2 is divided into two cavities by a partition. One cavity is used to install the motor assembly 3, and the other cavity is used to install the ball screw assembly. And a communication port is arranged on the partition close to the port side of the housing 2.

[0025] Exemplarily, in one embodiment, the motor assembly 3 includes: a rotating shaft, a rotor, a magnet, and a stator. The rotating shaft is rotatably arranged in the cavity of the housing 2. Wherein, the rotating shaft is in transmission connection with the screw rod 7 of the ball screw assembly through a gear transmission assembly; the rotor is arranged on the rotating shaft; the magnet is arranged on the outer periphery of the rotor; the stator is arranged on the wall surface of the cavity of the housing 2, and an annular gap is formed between the stator and the outer periphery of the rotor. That is, in this embodiment, the rotating shaft, the rotor, the magnet, the stator, and the housing 2 form a motor.

[0026] Exemplarily, in one embodiment, the gear transmission assembly includes: a gear shaft 4 and a double gear 5. The gear shaft 4 is arranged between the outer shell of the force sensor 1 and the partition in the communication port. Wherein, the gear shaft 4 is parallel to the rotating shaft; the double gear 5 is rotatably connected to the gear shaft 4 through a first deep groove ball bearing 6. Wherein, one gear of the double gear 5 meshes with the teeth arranged at the end of the rotating shaft; the other gear of the double gear 5 is in transmission connection with the input end of the ball screw assembly.

[0027] For example, in one embodiment, the ball screw assembly includes: a ball screw 7, a connecting column, a transmission gear, a ball nut 13 and a sealing assembly. The ball screw 7 is cylindrical and has a groove on the axial end face of the ball screw 7; the connecting column is coaxially arranged at the end of the ball screw 7, and the end of the connecting column away from the ball screw 7 is rotatably connected to the housing of the force sensor 1 through the second deep groove ball bearing 12; the transmission gear set is fixed to the connecting column, that is, in this embodiment, the transmission gear set is fixed to the second bearing 12 and the end of the ball screw 7 The connecting column between the parts is arranged on the outer ring of the bearing washer 10, and a bearing washer 9 is fixed on the outer ring of the bearing washer 10. A thrust needle bearing 8 is arranged between the bearing washer 9 and the transmission gear, and the gears of the transmission gear and the duplex gear 5 are meshed; the ball nut 13 is a long cylindrical structure, the ball nut 13 is threadedly connected to the ball screw 7, and the ball nut 13 extends out of the cavity of the housing 2 and is provided with an oil retaining sleeve 14 at the rear end thereof. The outer surface of the oil retaining sleeve 14 contacts the inner surface of the ball nut 13 for radial positioning, and the end of the oil retaining sleeve 14 is sealed by a heat insulation pad 18, that is, Figure 1 As shown, one side of the thermal insulation pad 18 is an annular ring, which is arranged between the outer ring of the oil retaining sleeve 14 and the inner ring of the ball nut 13. A thermal insulation pad clamping ring 19 is arranged between the inner ring of the ball nut 13 and the outer ring of the annular ring. The thermal insulation pad clamping ring 19 is used to fix the thermal insulation pad 18. The oil retaining sleeve 14 and the groove form a sealed cavity. The sealing assembly is arranged on the inner wall of the cavity that contacts the outer ring of the ball nut 13. In this embodiment, the sealing assembly includes: a sealing ring 16 and a dust ring 17, wherein the sealing ring 16 and the dust ring 17 are installed in the first installation groove defined in the inner wall of the cavity that contacts the outer ring of the ball nut 13.

[0028] Illustratively, in one embodiment, the dual gear 5 includes a large gear and a small gear, wherein the large gear is meshed with the teeth on the rotating shaft, and the small gear is meshed with the transmission gear on the ball screw.

[0029] Exemplarily, in one embodiment, a support guide ring 15 is further included. The support guide ring 15 is disposed in a second mounting groove formed on the inner wall of the cavity in contact with the outer ring of the ball nut 13 .

[0030] Illustratively, in one embodiment, the connecting column is rotatably connected to a groove provided on the side of the outer shell of the force sensor 1 facing the interior of the shell 2 through a second bearing 12, wherein a bearing retaining ring 11 is further provided on the connecting column on the side of the outer shell facing the force sensor 1, and a bearing pad 10 is further provided on the connecting column on the side facing the interior of the shell 2.

[0031] It should be noted that the upper surface of the transmission gear on the connecting column in the ball screw assembly is fitted with the inner surface of the force sensor 1 through a thrust needle roller bearing 8 and a bearing washer 9; the connecting column on the ball screw 7 is fitted with the inner surface of the second mounting groove on the outer shell of the force sensor 1 through a second deep groove ball bearing 12 and a bearing spacer ring 10; the lower part of the outer surface of the ball nut 13 in the ball screw assembly is fitted with the inner surface of the cavity of the housing 2 through a support guide ring 15, a sealing ring 16 and a dust ring 17; the outer surface of the ball screw 7 is a spiral semi-circular groove, and the lower surface of the transmission gear has an axially protruding limit step, and the limit between the ball screw 7 and the ball nut 13 is realized through the side surface of the limit step; the upper part of the inner surface of the ball nut 13 is a spiral semi-circular groove, and the outer surface of the upper end port of the ball nut 13 has an axially protruding limit step, and the limit between the ball screw 7 and the ball nut 13 is realized through the side surface of the limit step; the radii of the spiral semi-circular grooves on the inner surface of the ball nut 13 and the outer surface of the ball screw 7 are the same, and the spiral angles are also the same. When the spiral semi-circular grooves on the inner surface of the ball nut 13 and the outer surface of the ball screw 7 are fitted to form a complete circular spiral groove, a closed spiral raceway is formed, and the balls circulate and roll in the closed raceway loop composed of the ball screw 7 and the ball nut 13 during operation. The ball screw is radially positioned through the thrust needle roller bearing 8, the second deep groove ball bearing 12 and the support guide ring 15. The thrust needle roller bearing 8 is used to bear the reaction force generated during the operation of the ball screw 7 and transmit the force to the force sensor. The surface of the ball nut 13 that mates with the housing 2 is a guiding square hole, which is used to guide the ball nut 13 and restrict the rotation of the ball nut 13 during operation.

[0032] Working principle During use, the motor assembly 3 is powered on, that is, the rotating shaft, rotor, magnet, and stator of the motor assembly 3 and the housing 2 form a motor. After being powered on, the rotating shaft can be rotated. The rotation of the rotating shaft drives the double gear 5 to rotate. The rotation of the double gear 5 drives the ball screw 7 of the ball screw assembly to rotate through the transmission gear. The rotation of the ball screw 7 drives the ball nut 13 to expand and contract in the cavity of the housing 2, that is, the ball nut 13 acts as the output end of the actuator to perform the braking action. Among them, the outer shell of the force sensor directly serves as the cover of the opening end of the housing. When the output end of the ball screw assembly serves as the output end of the electric brake actuator, the reaction force generated during the operation of the ball screw assembly can be directly transmitted to the force sensor, reducing the force transmission loss and improving the measurement accuracy.

[0033] 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 principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electric brake actuator for a small unmanned aerial vehicle, characterized in that Comprising: A housing with one end open, inside which a ball screw assembly is provided. Wherein, the output end of the ball screw assembly penetrates through the housing as the output end of the electric brake actuator. A motor assembly disposed inside the housing, and the housing serves as the outer shell of the motor assembly. Its output end is drivingly connected to the input end of the ball screw assembly to drive the telescoping of the output end of the ball screw assembly. And a force sensor, which is provided as a cover on the port of the housing and is used to detect the reaction force generated by the ball screw assembly.

2. The electric brake actuator for a small unmanned aerial vehicle according to claim 1, characterized in that The housing is divided into two cavities by a partition. One cavity houses the motor assembly, and the other cavity houses the ball screw assembly. And a communication port is provided on the partition near the port of the housing.

3. The electro-brake actuator for a small unmanned aerial vehicle according to claim 2, characterized in that, The motor assembly includes: A rotating shaft rotatably disposed inside the cavity of the housing. Wherein, the rotating shaft is drivingly connected to the screw rod of the ball screw assembly through a gear transmission assembly. A rotor disposed on the rotating shaft. A magnet disposed on the outer periphery of the rotor. And a stator disposed on the wall surface of the cavity of the housing and forming an annular gap with the outer periphery of the rotor.

4. The electro-brake actuator for a small unmanned aerial vehicle according to claim 3, wherein The gear transmission assembly includes: A gear shaft disposed between the outer shell of the force sensor and the partition inside the communication port. Wherein, the gear shaft is parallel to the rotating shaft. And a double gear rotatably connected to the gear shaft through a first deep groove ball bearing. Wherein, one gear of the double gear meshes with the teeth provided at the end of the rotating shaft; the other gear of the double gear is drivingly connected to the input end of the ball screw assembly.

5. The electro-brake actuator for a small unmanned aerial vehicle according to claim 4, characterized in that, The ball screw assembly includes: A ball screw having a groove opened on the end face along its axis. A connecting column coaxially disposed at the end of the ball screw and rotatably connected to the outer shell of the force sensor. A transmission gear sleeved and fixed on the connecting column, and the transmission gear meshes with the gear of the double gear. A ball nut, which is of a long cylinder structure and is threadedly connected to the ball screw. A grease retainer is provided inside the rear end of the ball nut extending out of the cavity of the housing. The end provided with the grease retainer is sealed by a heat insulation pad, and a sealed cavity is formed between the grease retainer and the groove. And a sealing assembly disposed on the inner wall of the cavity in contact with the outer ring of the ball nut.

6. The electro-brake actuator for a small unmanned aerial vehicle according to claim 5, characterized in that, The double gear includes a large gear and a small gear. Wherein, the large gear meshes with the teeth on the rotating shaft, and the small gear meshes with the transmission gear on the ball screw.

7. The electro-brake actuator for a small unmanned aerial vehicle according to claim 5, characterized in that 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 first installation groove opened on the inner wall of the cavity in contact with the outer ring of the ball nut.

8. The electro-brake actuator for a small unmanned aerial vehicle according to claim 5, characterized in that, A support ring is further included, which is disposed in a second installation groove opened on the inner wall of the cavity in contact with the outer ring of the ball nut.

9. The electro-brake actuator for a small unmanned aerial vehicle according to claim 5, wherein, The connecting column is rotatably connected to a groove provided on the side of the outer shell of the force sensor facing the inside of the housing through a second bearing. Wherein, a bearing snap ring is further provided on the connecting column facing the outer shell of the force sensor, and a bearing spacer ring is further provided on the connecting column facing the inside of the housing.

10. The electro - brake actuator for a small unmanned aerial vehicle according to claim 9, characterized in that, The transmission gear is disposed on the connecting column between the second bearing and the end of the ball screw, and a bearing washer is sleeved and fixed on the outer ring of the bearing spacer ring, and a thrust needle roller bearing is provided between the bearing washer and the transmission gear.

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