Actuator arrangement for an electromechanically operated brake

Abstract

The present disclosure relates to the field of brake-by-wire system technology and specifically to an actuator structure for an electromechanical brake, comprising: A jaw pliers assembly, An actuator assembly detachably mounted on the jaw assembly, the actuator assembly comprising an upper housing, a middle housing and a lower housing connected sequentially, A gear mechanism and a pressure sensor are arranged in the lower housing, with the gear mechanism being connected to an electric motor. The output shaft of the electric motor is located in the lower housing, while the stationary end of the electric motor is arranged in the jaw assembly and the output shaft is connected to the gear mechanism. The middle housing contains a printed circuit board, with the middle housing separating the gear mechanism from the printed circuit board. The lower housing serves to encapsulate the circuit board and dissipate its heat. According to the present disclosure, the actuator assembly is designed as a three-part structure with upper, middle and lower housing, which allows for easy assembly and sealing, reduces costs and increases production and assembly efficiency.

Description

TECHNICAL AREA

[0001] The present disclosure relates to the field of brake-by-wire system technology and specifically to an actuator structure for an electromechanical brake. TECHNOLOGY STANDPOINT

[0002] Electromechanical brakes differ from conventional hydraulic brakes and electronic parking brakes (EPBs) in that their actuator comprises not only an electric motor and a mechanical gear mechanism, but also a printed circuit board assembly (PCBA). Conventional EPB-standard solutions integrate the motor, gear, and PCBA into a single housing, resulting in complex assembly processes and large dimensions. The actuator according to patent CN220465471U cannot be separated from the caliper, has irregular housing and PCBA shapes, requires symmetrical dual circuit boards, and features a complex caliper structure, making manufacturing more difficult and increasing costs. While patents CN116872902A and CN219969653U allow for separation from the caliper, the planetary gear teeth can detach after separation, preventing the actuator from functioning as a standalone component.The use of a support frame to separate the gearbox and electronics has the disadvantage that, as a gear axle, it does not allow precise positioning with the gearbox mechanism in the lower housing and requires additional welding features, resulting in uncompact dimensions.

[0003] For this reason, the present disclosure provides an actuator structure for an electromechanical brake that overcomes the disadvantages of the previous technology. SUMMARY OF THE INVENTION: Purpose of the Revelation:

[0004] Provision of an actuator structure for an electromechanical brake to solve the problems of complex assembly processes for motor, gearbox structure and circuit board, insufficient compactness and lack of assembly accuracy in the existing technology. Technical solution of the revelation:

[0005] An actuator structure for an electromechanical brake, comprising: A brake caliper assembly;

[0006] An actuator assembly detachably connected to the brake caliper assembly, wherein the actuator assembly comprises an upper housing, a middle housing and a lower housing connected to each other in that order;

[0007] A gearbox unit and a pressure sensor are arranged in the lower housing, with the gearbox unit being connected to an electric motor;

[0008] The electric motor comprises a stationary end and an associated output shaft, the output shaft being located in the lower housing and the stationary end being attached to the brake caliper assembly;

[0009] The output shaft is connected to the gearbox unit;

[0010] The central housing contains a printed circuit board, with the central housing separating the gearbox unit from the printed circuit board;

[0011] The upper / lower housing encloses the circuit board and serves to dissipate heat from its heat.

[0012] Preferably, the gear unit comprises a first spur gear, a planetary gear set and an output gear, wherein the first spur gear is arranged on the output shaft, the first spur gear engages with the output gear via an idler gear, the output gear is arranged coaxially with the planetary gear set, and a parking lock is additionally installed in the lower housing.

[0013] Preferably, the parking device comprises a ratchet, a pawl lever that engages the teeth of the ratchet and thereby blocks its rotation, a solenoid valve for driving a portion of the pawl lever towards or away from the ratchet, and a spring element. The spring force of the spring element moves a portion of the pawl lever away from or towards the ratchet.

[0014] The ratchet is mounted on the output shaft and is located between the stationary end of the electric motor and the first gear. The stationary part of the pawl lever is rotatably connected to the lower housing via a guide shaft. One end of the spring element is rigidly connected to the lower housing via the guide shaft, while the other end is connected to the rotating part of the pawl lever. The solenoid valve is rigidly connected to the lower housing and drives the pawl lever to rotate around the corresponding guide shaft, thereby moving the rotating part of the pawl lever away from or towards the ratchet.

[0015] Preferably, the planetary gear set comprises one or more planet gears and a sun gear meshing with the planet gears. The planetary gear set further includes a first carrier (bridge) and a ring gear. The sun gear is mounted on the side of the output gear facing the planet gear and meshes with the planet gear. The planet gears mesh with the ring gear. The positional deviation between the mounting bore of the ring gear, the guide bore of the intermediate gear shaft, the positioning fixing of the first carrier, and the mounting bore of the electric motor is less than 0.03 mm.

[0016] Preferably, the joint between the lower housing and the middle housing is sealed with sealant along the edge. Likewise, the joint between the upper housing and the middle housing is sealed with sealant. Furthermore, the edge of the middle housing has several screw holes and is connected to the lower housing by screws.

[0017] Preferably, the middle housing has a precisely fitting cavity whose position and shape correspond to the parking device and the gear mechanism. When the middle housing is connected to the lower housing, the cavity encloses the parking device and the gear mechanism.

[0018] Preferably, three through-holes are provided in the central housing, each corresponding to the pin positions of the solenoid valve, the motor, and the terminal block of the pressure sensor. After the pins have been inserted through the corresponding through-holes, these are sealed using a sealing method.

[0019] Preferably, the middle housing has reinforcing ribs on the side facing the upper housing. In addition, several mounting pillars are arranged along the edge of the middle housing for securing it to the circuit board.

[0020] Preferably, the central housing has several fixing points that correspond to the positions of the capacitors on the circuit board. Vibration-damping materials are attached to these fixing points.

[0021] Preferably, the upper and middle housings are connected to each other by snap-fit ​​connections. The upper housing has reinforcing ribs extending towards the middle housing, which are coated with thermally conductive adhesive.

[0022] Advantages of the present disclosure compared to the prior art: (1) The actuator is designed in three parts (upper housing, middle housing and lower housing), which allows for easy assembly and sealing, reduces costs and increases production and assembly efficiency. (2) The actuator and the brake caliper assembly are connected in a way that allows for disassembly, which increases system flexibility and offers better processing characteristics. (3) The high positional accuracy between the mounting holes of the ring gear of the planet gears, the guide hole of the intermediate gear and the motor mounting hole ensures smooth running of the gears, high efficiency and low noise. (4) The central housing separates the printed circuit board from the gear mechanism, thus protecting the printed circuit board from damage caused by grease and mechanical components, which increases reliability. (5) The connection between the upper housing, middle housing and lower housing by means of sealant ensures water and dustproof properties. (6) The through-holes provided in the central housing for the insertion of pins reduce the assembly effort, reduce the overall dimensions of the actuator and enable a more compact design. EXAMPLES OF EXECUTION

[0023] The invention is described by reference to the Fig. 1-7 are described in detail, with particular attention paid to the following innovations: Precision gearbox with planetary gear set (42) and detent mechanism (44) Vibration-damped PCB mounting (223) with decoupling points Thermally optimized housing structure with heat-conducting fins (211) Multi-axis bearing topology for high positional accuracy DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a schematic representation of the actuator structure of an electromechanical brake according to the present disclosure; Fig. Figure 2 shows a schematic representation of the actuator assembly; Fig. Figure 3 shows a view of the interaction side between the actuator assembly and the brake caliper assembly; Fig. Figure 4 shows a view of the lower casing and internal structure; Fig. Figure 5 shows an exploded view of the lower casing and internal structure; Fig. Figure 6 shows an exploded view of the assembly between the middle housing and the upper housing; Fig. Figure 7 shows an exploded view of the assembly between the middle housing and the lower housing.

[0024] where: 1. Brake caliper assembly: 11. First mating surface; 2. Actuator assembly: 21. Upper housing; 211. Stiffening rib; 22. Center housing; 221. Profiled chamber; 222. Through hole; 223. Fixing point; 23. Lower housing; 231 Lower support structure; 232 Support arm 3 Electric motor; 31. Drive shaft 4. Gear assembly 41. First spur gear; 42 Planetary gear set; 421 Planetary gear 422 First carrier; 4221 Second mating surface 423 Ring gear 43 Idler gear 44 Parking lock 441 Ratchet gear 442 Solenoid valve 443 Pawl 444 Spring element 45 Output gear 5. Pressure sensor 6. Circuit board EXECUTION DESCRIPTION

[0025] The present disclosure will be explained in detail below using specific examples: As in Fig. As shown in Figures 1-2, the actuator structure of an electromechanical brake comprises a brake caliper assembly (1) and a detachably mounted actuator assembly (2). The first mating surface (11) of the brake caliper assembly engages with the second mating surface (4221) of the actuator assembly. In this embodiment, the first mating surface (11) is designed as a gear and the second mating surface (4221) as a corresponding toothed ring, with the former engaging with the latter. The detachable mounting increases system flexibility and process quality, thereby improving braking performance and vehicle safety.

[0026] The actuator assembly (2) features a three-part housing design consisting of an upper housing (21), a middle housing (22), and a lower housing (23). This modular design simplifies assembly, sealing, and production processes, reduces manufacturing costs, and enables precise coaxiality. The three-part structure ensures uniform stress distribution under load, thereby increasing stability and service life, while simultaneously minimizing friction and optimizing efficiency.

[0027] As in the Fig. As shown in Figures 2-3, a gear mechanism (4) and a pressure sensor (5) are arranged in the lower housing (23). The gear mechanism (4) is connected to an electric motor (3), with the mounted end of the electric motor (3) positioned in the brake caliper assembly (1). The output shaft (31) of the electric motor (3) is located inside the lower housing (23) and is coupled to the gear mechanism (4). When the electric motor (3) is switched on, the output shaft (31) is set into rotation, thereby actuating the gear mechanism (4). This causes the brake caliper assembly (1) to move and thus triggers the braking process.

[0028] The central housing (22) contains a printed circuit board (6) which serves to control the electric motor (3) and the gear mechanism (4). At the same time, the central housing (22) acts as a separating barrier between the printed circuit board (6) and the gear mechanism (4) to prevent the printed circuit board from being affected by moving gear components or lubricants.

[0029] During operation, the gear mechanism (4) can generate vibrations, noise, and electromagnetic interference that could damage the printed circuit board (6). Separation by means of the central housing (22) minimizes these negative influences, thereby increasing system stability and protecting the printed circuit board (6) from damage.

[0030] Furthermore, the gear mechanism (4) may contain rapidly rotating components, sharp edges, or high temperatures. The central housing (22) prevents direct contact of these critical areas with the circuit board (6), thereby improving the safety of the entire actuator system.

[0031] The upper housing (21) connected to the middle housing (22) encloses the circuit board (6) and also serves to dissipate heat to prevent overheating of the electronic components.

[0032] Furthermore, as in the Fig. Figures 4 to 5 show the transmission mechanism (4) comprising a first gear (41) and a planetary gear set (42). The first gear (41) is located on the output shaft (31) and engages with the planetary gear set (42) via an intermediate gear (43). The power transmission via the intermediate gear (43) allows the first gear (41) to engage precisely with the planetary gear set (42), thereby minimizing power losses during transmission and increasing efficiency.

[0033] The arrangement of the first gear (41) on the output shaft (31) contributes to saving space, enables a reduction in the overall dimensions of the transmission system and leads to a more compact design of both the transmission mechanism (4) and the actuator assembly (2).

[0034] At the same time, the intermediate gear (43) acts as a buffer and damping element. During power transmission from the first gear (41) via the intermediate gear (43) to the planetary gear (42), the intermediate gear (43) is able to absorb some of the vibrations and shocks, thereby reducing vibrations and noise during the power transmission process.

[0035] The lower housing (23) further comprises a parking lock (44). The parking lock (44) consists of a ratchet (441), a solenoid valve (442), a pawl (443), and a spring element (444). In this embodiment, the spring element (444) is designed as a spring.

[0036] The ratchet (441) is arranged on the output shaft (31) and is located between the electric motor (3) and the first gear (41). The pawl (443) is rotatably mounted on the lower housing (23). One end of the spring element (444) is attached to the lower housing (23) via a guide shaft, while the other end is attached to the rotatable part of the pawl (443).

[0037] The solenoid valve (442) is fixed to the lower housing (23). When power is supplied, the solenoid valve (442) generates a magnetic force, which moves the pawl (443) into a specific position. In this position, its rotatable part engages in the tooth gaps of the ratchet (441) and thus prevents it from rotating backward, thereby activating the parking function.

[0038] To release the park position, the power supply to the solenoid valve (442) is interrupted. The spring element (444) then moves the pawl (443) out of the tooth gaps of the ratchet (441), allowing it to rotate freely and enabling the vehicle to move.

[0039] To improve the high-precision positioning of the lower housing (23), the planetary gear (42) comprises one or more planet gears (421), a sun gear meshing with the planet gears (421), as well as a first support (422), a ring gear (423), and an output gear (45), which support the planetary gear (42) and ensure its stable operation. The output gear (45) meshes with the intermediate gear (43). The outer wall of the ring gear (423) is fixed to the lower housing (23), while its inner wall meshes with the planet gears (421).

[0040] When driven by the intermediate gear (43), the driven gear (45) rotates. The sun gear mounted on the driven gear (45) rotates with it and thereby drives the planet gears (421), which in turn set the first carrier (422) and its second coupling section (4221) into rotation, thus synchronously rotating the first coupling section (11) of the brake caliper assembly (1).

[0041] The positional deviation between the mounting holes of the ring gear (423), the guide bore of the intermediate gear axle (43), the positioning device of the first support (422), and the motor mounting holes (3) is less than 0.03 mm. This minimizes inaccuracies in power transmission due to assembly tolerances. The precise fit reduces friction and vibration between the components, resulting in lower operating noise and smoother running. The high-precision drilling and positioning methods also simplify component replacement and maintenance.

[0042] The lower housing (23) has a lower support bracket (231) against which the side of the first support (422) facing away from the output gear (45) rests. The lower support bracket (231) has a through-hole through which the second coupling section (4221), projecting from the main body of the first support (422), is guided to connect with the first coupling section (11) of the brake caliper assembly (1).

[0043] This arrangement of the lower support carrier (231) limits the freedom of movement of the planetary gear (42) and prevents the planet gears (421) or the entire planetary gear (42) from falling out during disassembly, thus making the actuator assembly (2) easily removable as an independent component unit.

[0044] In this embodiment, the through-hole of the lower support bracket (231) does not have a round cross-section, but forms a circular segment created by a secant outside the center of the circle. The separated area serves as a holder for the pressure sensor (5).

[0045] In addition, the actuator assembly (2) in this embodiment comprises a support arm (232) with a cross-shaped main body and a central guide pin. The main body has four secondary arms, the ends of which are each connected to the lower housing (23) by fastening elements such as screws. The guide pin passes successively through the output gear (45) and the gear carrier (422) to fix their lateral position.

[0046] To provide dust and water protection for the actuator assembly (2), the connection between the lower housing (23) and the middle housing (22) has a sealant along its edge and is additionally secured by screws. The connection between the upper housing (21) and the middle housing (22) is also sealed with a sealant. The sealant fills microscopic gaps at the connection points and effectively prevents the ingress of liquids or gases, thus protecting internal components from corrosion and contamination.

[0047] After curing, the sealant forms a solid bonding layer which, in combination with the screw connection, increases the mechanical stability between the lower housing (23) and the middle housing (22). This prevents the connection from loosening or coming undone due to vibrations or shocks.

[0048] Furthermore, as in the Fig. As shown in Figures 6 to 7, the middle housing (22) has a precisely fitting cavity (221) whose position and shape correspond to the parking lock (44) and the gear mechanism (4). When the middle housing (22) is connected to the lower housing (23), the cavity (221) encloses the parking lock (44) and the gear mechanism (4).

[0049] This precise adjustment ensures: 1. Precise positioning during assembly 2. Reduction of assembly errors and difficulties 3. -Prevention of delays or relaxations in operations 4. - Increased overall stability and reliability 5. Compact and efficient integration of components

[0050] Additionally, ribs on the side of the middle housing (22) facing the upper housing (21) reinforce its structure and prevent deformation. Mounting pillars on the edge of the middle housing (22) serve to secure the printed circuit board (6).

[0051] To completely separate mechanical and electronic components, the central housing (22) contains three through-holes (222), each corresponding to the pin positions of: 6. Solenoid valve (442) 7. Motor (3) 8. Pressure sensor interface (5) correspond. After inserting the pins, the holes (222) are sealed. This sealing: 1. Reduces contact resistance 2. Increases electrical connection stability 3. Prevents environmental influences and short circuits 4. Ensures safe operation

[0052] As in Fig. As shown in Figure 6, the central housing (22) has several fixing points (223) for stabilizing the capacitors on the circuit board (6). These fixing points correspond precisely to the positions of the capacitors on the circuit board (6). Vibration-damping material at these fixing points increases the reliability of the electronic components in the event of vibrations of the actuator assembly (2).

[0053] As in Fig. As shown in Figure 6, a rib (211) projecting towards the middle housing (22) is formed in the upper housing (21) to improve the heat dissipation efficiency of the printed circuit board (6). A thermal paste is applied to the rib (211).

[0054] The rib (211) provides the following advantages: 1. Increase in contact area without increasing the overall volume 2. Increased heat dissipation efficiency 3. The thermal paste further increases the contact area. 4. Enables faster heat transfer from the center housing (22) to the fin (211) 5. Effective heat dissipation is thereby ensured. Implementation principle of this embodiment:

[0055] The actuator assembly (2) is mounted with the brake caliper assembly (1). The circuit board (6) controls the start of the electric motor (3), which sets the output shaft (31) into rotation. The first gear (41) rotates together with the output shaft (31) and transmits the motion via the intermediate gear (43) to the output gear (45). The sun gear connected to the output gear (45) then sets the planet gears (421) in motion, which actuates the brake caliper and initiates braking.

[0056] For the parking brake function, the solenoid valve (442) is energized and generates a magnetic force. The pawl (443) moves into a position where its rotatable part engages the teeth of the ratchet (441) and blocks its reverse rotation. To release the parking brake, the power supply to the solenoid valve (442) is interrupted, whereupon the spring element (444) retracts the pawl (443) from the teeth of the ratchet (441), allowing it to rotate freely and enabling the vehicle to move.

[0057] The central housing (22) insulates the circuit board (6) from the gear mechanism (4), thus protecting it from electromagnetic interference and thermal stress. Simultaneously, the pressure sensor (5) precisely measures the brake pressure in real time, enabling immediate pressure regulation and control. Note regarding the demarcation of the protected area:

[0058] The present embodiment serves only to illustrate the technical concept of this disclosure. Its purpose is to make the content accessible to those skilled in the art for implementation without limiting the scope of protection. It is obvious to those skilled in the art that this disclosure is not limited to the exemplary embodiments shown. Rather, it can be realized in other concrete forms without deviating from its essence. Therefore, all embodiments are to be considered exemplary and non-limiting. The scope of protection is defined by the attached claims, not by the foregoing description. All modifications that correspond to the equivalent meanings and scope of the claims are thus included in this disclosure. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 220465471U

[0002] CN 116872902A

[0002] CN 219969653U

[0002]

Claims

[1] Actuator structure for an electromechanical brake, characterized by : a jaw pliers assembly (1), an actuator assembly (2) which is detachably connected to the jaw clamp assembly (1), wherein the actuator assembly (2) comprises an upper housing (21), a middle housing (22) and a lower housing (23), the upper housing (21), the middle housing (22) and the lower housing (23) are connected to each other in this order, In the lower housing (23) a gear mechanism (4) and a pressure sensor (5) are arranged, the gear mechanism (4) is connected to an electric motor (3), the output shaft (31) of the electric motor (3) is located in the lower housing (23), while the stationary end of the electric motor (3) is arranged in the jaw assembly (1), the output shaft (31) is connected to the transmission mechanism (4), The middle housing (22) contains a circuit board (6), the middle housing (22) separates the gear mechanism (4) from the circuit board (6), The upper housing (21) encapsulates the circuit board (6) and serves to dissipate its heat. [2] Actuator structure according to claim 1, characterized by , that: the gear mechanism (4) comprises a first gear (41), a planetary gear (42) and a driven gear (45), the output shaft (31) is encased with the first gear (41), the first gear (41) engages with the driven gear (45) via an idle gear (43), the driven wheel (45) is arranged coaxially to the planetary gear (42), A parking mechanism (44) is additionally installed in the lower housing (23). [3] Actuator structure according to claim 2, characterized by , that: the parking mechanism (44) comprises a pawl (441), a solenoid valve (442), a locking lever (443) and a spring element (444), the pawl (441) is mounted on the output shaft (31) between the stationary end of the electric motor (3) and the first gear (41), the fixed end of the locking lever (443) is rotatably connected to the lower housing (23) via a guide shaft, one end of the spring element (444) is rigidly connected to the lower housing (23) via the guide shaft, while the other end is connected to the rotatable part of the locking lever (443), the solenoid valve (442) is fixedly connected to the lower housing (23) and rotates the locking lever (443) around the guide shaft so that its rotatable end moves away from or closer to the pawl (441). [4] Actuator structure according to claim 2, characterized by , that: the planetary gear (42) comprises one or more planet gears (421) and a sun gear meshing with them, the planetary gear (42) further comprises a first support (422) and a ring gear rim (423), the sun gear is attached to the side of the driven gear (45) that faces the planet gears (421) and engages with them, the positional deviation between the bore of the ring gear ring (423), the guide shaft of the idler wheel (43), the mounting of the first support (422) and the motor mount (3) is less than 0.03 mm. [5] Actuator structure according to claim 1, characterized by , that: the connection point between the lower housing (23) and the middle housing (22) is provided with sealant along the edge, the connection point between the upper housing (21) and the middle housing (22) is also sealed with sealant, Several screw holes are distributed around the edge of the middle housing (22), through which it is screwed to the lower housing (23). [6] Actuator structure according to claim 2, characterized by , that: the middle housing (22) has a precisely fitting recess (221) whose position and shape correspond to the parking mechanism (44) and the gear mechanism (4), When the middle housing (22) is connected to the lower housing (23), the recess (221) encloses the parking mechanism (44) and the gear mechanism (4). [7] Actuator structure according to claim 3, characterized by , that: the middle housing (22) has three through holes (222) which each correspond to the pins of the solenoid valve (442), the electric motor (3) and the pressure sensor (5), After the pins have been inserted through the respective holes (222), these are sealed using a sealing process. [8] Actuator structure according to claim 1, characterized by , that: the side of the middle housing (22) facing the upper housing (21) is provided with stiffening ribs, Several mounting columns are arranged along the edge, which serve to fix the printed circuit board (6). [9] Actuator structure according to claim 1, characterized by , that: the middle housing (22) has several fixing points (223) which correspond to the capacitor positions on the circuit board (6), the fixing points (223) are equipped with vibration-damping material. [10] Actuator structure according to claim 1, characterized by , that: the upper housing (21) and the middle housing (22) are joined together by snap connections, the upper housing (21) has inwardly directed reinforcing ribs (211) which are coated with thermal paste

Images