Electromechanical actuator for drum brake and drum brake system

Abstract

The utility model discloses an electromechanical actuator for a drum brake and a drum brake system. An electromechanical actuator for a drum brake includes a power mechanism having an output shaft capable of forward and reverse rotation; the main braking mechanism comprises a rotating transmission part, the rotating transmission part and the output shaft are parallel to each other and arranged at an interval, and the rotating transmission part is provided with a first end and a second end opposite to each other; the transmission mechanism is connected between the output shaft and the rotary transmission part, the output shaft can drive the rotary transmission part to move in the direction from the second end to the first end when rotating forwards, and the output shaft can drive the rotary transmission part to move in the direction from the first end to the second end when rotating backwards. According to the electronic mechanical actuator for the drum brake and the drum brake system, the structure is simple, the number of parts is small, the occupied space is small during assembly, maintenance and replacement are convenient, and meanwhile energy consumption is low in the braking process.

Description

Technical Field

[0001] The present application belongs to the field of vehicle technology, and in particular relates to an electromechanical actuator for a drum brake and a drum brake system. Background Art

[0002] With the continuous development of vehicle electronic control technology, wire control braking represented by electronic mechanical braking has become the key development direction of vehicle braking technology due to its advantages of high efficiency, low energy consumption and high integration.

[0003] Existing braking systems typically use pneumatic systems to actuate the brakes. This principle works by using an air compressor to generate high-pressure gas, which pushes against a diaphragm within an air chamber, driving the brake push rod to displace and achieve braking. However, pneumatic systems are bulky and complex, with numerous parts, occupying significant space within the vehicle chassis and making component replacement difficult. Furthermore, pneumatic systems rely on air as a medium to transmit pressure, which generates losses during the process, resulting in high overall energy consumption for the braking system. Utility Model Content

[0004] The electromechanical actuator and drum brake system for drum brakes provided in the embodiments of the present application have a simple structure, fewer components, take up less space during assembly, are easy to repair and replace, and achieve low energy consumption during braking.

[0005] An embodiment of the present application provides an electromechanical actuator for a drum brake, wherein the electromechanical actuator for a drum brake includes:

[0006] The power mechanism comprises an output shaft capable of forward and reverse rotation, and having a first output end and a second output end disposed opposite to each other;

[0007] A main brake mechanism includes a rotating transmission member, the rotating transmission member and the output shaft are parallel to each other and spaced apart, the rotating transmission member having a first end and a second end opposite to each other;

[0008] a transmission mechanism connected between the first output end and the rotating transmission member, capable of driving the rotating transmission member to move in a direction from the second end to the first end when the output shaft rotates forward, and capable of driving the rotating transmission member to move in a direction from the first end to the second end when the output shaft rotates reversely;

[0009] The auxiliary braking mechanism is connected to the second output end.

[0010] The electromechanical actuator for a drum brake as described above, wherein the transmission mechanism includes a driving gear and a driven gear, the driving gear is fixedly connected to the output shaft, the driven gear is sleeved on the rotating transmission member, and the driven gear is directly or indirectly screwed to the rotating transmission member, and the driving gear and the driven gear are meshed and connected;

[0011] The output shaft drives the driving gear to rotate synchronously, and the driving gear drives the driven gear to rotate and rotates relative to the rotary transmission member to drive the rotary transmission member to reciprocate along its axial direction.

[0012] In the electromechanical actuator for drum brakes as described above, the main brake mechanism includes a sleeve, which is sleeved and screwed to the rotating transmission member; and the driven gear is fixedly sleeved on the outside of the sleeve.

[0013] As described above, the electromechanical actuator for drum brakes, wherein a positioning groove is recessed on the outer circumferential surface of the sleeve, a tolerance ring is fixedly embedded in the positioning groove, the outer circumferential surface of the tolerance ring protrudes from the outer circumferential surface of the sleeve, and the driven gear is fixedly sleeved on the tolerance ring.

[0014] The electromechanical actuator for a drum brake as described above, wherein the electromechanical actuator for a drum brake has a housing, the housing comprising a first shell and a second shell that are detachably connected, the first shell and the second shell cooperate to form a cavity;

[0015] The transmission mechanism is located inside the cavity;

[0016] A portion of the power mechanism is disposed outside the housing, and the output shaft passes through the housing and extends into the cavity to be connected to the transmission mechanism;

[0017] A portion of the main braking mechanism is located inside the first housing and connected to the transmission mechanism, and the first end of the rotating transmission member extends through and out of the first housing.

[0018] The electromechanical actuator for a drum brake as described above, wherein a bearing is fixedly sleeved on the outer circumferential surface of the sleeve, a limiting groove is recessed on the inner surface of the first housing and / or the second housing, the bearing is disposed in the limiting groove, and the outer surface of the bearing is loosely fitted with the groove wall of the limiting groove;

[0019] A pressure ring is fixedly mounted on the outer circumference of the sleeve. The pressure ring is located between the bearing and the driven gear, and is spaced apart from the driven gear. The pressure ring contacts the surface of the bearing facing the driven gear.

[0020] The electromechanical actuator for a drum brake as described above, wherein, along the direction from the first end to the second end of the rotating transmission member, the rotating transmission member includes a first section, a second section, and a third section connected in sequence, and at least a portion of the first section extends through the outside of the first housing;

[0021] The electromechanical actuator for a drum brake further includes a second housing, the second housing being in communication with the first housing, and a portion of the second section and the third section penetrating the first housing and extending into the interior of the second housing.

[0022] The electromechanical actuator for a drum brake as described above, wherein the third section is provided with a limiting hole extending radially through the rotating transmission member, and the limiting hole is a strip-shaped hole extending axially along the rotating transmission member;

[0023] The main brake mechanism further includes a limiting pin shaft, which passes through the limiting hole in a radial direction of the rotating transmission member, and both ends of the limiting pin shaft are respectively connected to the second housing.

[0024] As described above, the electromechanical actuator for a drum brake is provided with a guide ring on the third section, and both ends of the limit pin shaft respectively pass through the guide ring, the inner surface of the guide ring is in sliding contact with the outer peripheral surface of the third section, and the outer surface of the guide ring is in sliding contact with the inner surface of the second shell.

[0025] The electromechanical actuator for drum brakes as described above, wherein the limit pin is provided with a lubricating sleeve;

[0026] And / or, both ends of the limiting pin shaft respectively pass through the second shell, and a sealing member is provided between the limiting pin shaft and the second shell.

[0027] In the electromechanical actuator for drum brakes as described above, the auxiliary brake mechanism is a power-off brake.

[0028] As described above, the electromechanical actuator for drum brakes, wherein the auxiliary braking mechanism includes a ratchet, a positioning pawl and a magnetic component, the ratchet is connected to the output shaft, and the output shaft drives the ratchet to rotate synchronously; the positioning pawl is arranged on one side of the circumference of the ratchet, and the magnetic component is connected to the positioning pawl, and the magnetic component is used to drive the positioning pawl to engage or separate with the ratchet positioning hook.

[0029] The electromechanical actuator for drum brakes as described above, wherein the electromechanical actuator for drum brakes further includes a third housing, the third housing is detachably connected to the power mechanism, and the second output end and the auxiliary braking mechanism are both arranged inside the third housing, and the positioning pawl is rotatably connected to the third housing.

[0030] The electromechanical actuator for a drum brake as described above, wherein the magnetic assembly comprises a first magnet and a second magnet, and both the first magnet and the second magnet are bistable electromagnets;

[0031] The second magnet is mounted on the positioning pawl;

[0032] The electromechanical actuator for a drum brake further includes a controller, which is disposed inside the third housing and is electrically connected to the power mechanism and the first magnet, respectively.

[0033] An embodiment of the present application further provides a drum brake system, wherein the drum brake system includes the electromechanical actuator for a drum brake as described above.

[0034] The electronic mechanical actuator and drum brake system for drum brakes in the embodiments of the present application can drive the main brake mechanism and / or auxiliary brake mechanism to operate through the transmission mechanism, thereby driving the push rod movement of the drum brake system to realize the operation of the drum brake system, wherein when the output shaft of the power mechanism rotates forward, it can provide thrust to the push rod, and when the output shaft of the power mechanism reverses, it can provide pulling force to the push rod, thereby adjusting the braking state, and can effectively replace the pneumatic system in the existing drum brake system. Compared with the pneumatic system of the existing drum brake system, it has the effects of simple structure, small number of parts, small assembly space, easy maintenance and replacement, and reduced operating energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 A schematic structural diagram of an electromechanical actuator for a drum brake provided in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of the internal structure of an electromechanical actuator for a drum brake provided in an embodiment of the present application;

[0038] Figure 3A schematic cross-sectional view of an electromechanical actuator for a drum brake provided in an embodiment of the present application;

[0039] Figure 4 A schematic structural diagram of a main brake mechanism of an electromechanical actuator for a drum brake provided in an embodiment of the present application;

[0040] Figure 5 for Figure 1 Schematic diagram of the cross-section of the local structure;

[0041] Figure 6 This is a structural schematic diagram of the auxiliary braking mechanism of the electromechanical actuator for drum brakes provided in this application.

[0042] Description of Figure Numbers:

[0043] 1. Power mechanism; 11. Output shaft; 111. First output end; 112. Second output end; 2. Main brake mechanism; 21. Rotating transmission member; 211. First end; 212. Second end; 213. First section; 214. Second section; 215. Third section; 2151. Limit hole; 22. Sleeve; 221. Positioning groove; 23. Tolerance ring; 24. Bearing; 25. Pressing ring; 26. Limit pin; 27. Guide ring; 28. Lubricating sleeve; 29. Seal; G. Ball; 3. Transmission mechanism; 31. Driving gear; 32. Driven gear; 4. First housing; 5. Second housing; 6. Auxiliary brake mechanism; 61. Ratchet; 62. Positioning pawl; 63. Magnetic assembly; 631. First magnet; 632. Second magnet; 7. Third housing; 8. Controller; 9. Double-headed shift fork; S. Limit groove. DETAILED DESCRIPTION

[0044] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present application by illustrating the examples of the present application.

[0045] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, the elements defined by the phrase "comprising..." do not exclude the presence of other identical elements in the process, method, article, or device comprising the elements.

[0046] The applicant has found that in the prior art, there is a lack of electronic braking technology for drum brakes, and the following problems still need to be solved:

[0047] 1. Structural integration requirements: Limited by the demands for compact vehicle chassis space and component interchangeability, the development and application of electronic mechanical brakes not only face the challenge of compact vehicle axial space, but also need to consider the difficulty of component replacement;

[0048] 2. Structural simplification: Existing drum brakes typically use pneumatic braking. This principle involves using an air compressor to generate high-pressure gas, which pushes the diaphragm in the air chamber, causing the push rod to move. Ultimately, the brake shoe rotates the friction lining, which contacts the brake drum, generating braking force. This overall structure is bulky and complex, with many parts and a large footprint.

[0049] 3. Low energy consumption: Traditional pneumatic brakes rely on air as a medium for transmission. Their structure, including but not limited to an air compressor, air dryer, air reservoir, and brake chamber, is complex and inefficient. Similarly, hydraulic brakes also rely on brake fluid to transmit pressure. The losses incurred by the fluid pressure still exist, and energy consumption is also high.

[0050] 4. Fast response and high-precision adjustment: The response time of pneumatic brakes and hydraulic brakes depends on the pressure and length of the pipeline. For large commercial vehicles, where the pressure difference between the brake and the wheel end is large and the pipeline is long, the pressure build-up time will be long, resulting in slow braking response. In addition, the braking force of the above two brakes needs to be provided by liquid / gas pressure. During the braking process, there is usually a pressure difference at both ends of the pipeline, resulting in a deviation between the required braking force and the actual braking force. In addition, the parameters of the left and right wheels of the drum brake are inconsistent, which ultimately leads to unbalanced braking force on the left and right wheels, causing the vehicle to brake off track, and unable to meet the growing demand for high-precision braking.

[0051] In view of the above problems, the applicant proposes an electromechanical actuator for a drum brake, wherein the electromechanical actuator for a drum brake comprises a power mechanism 1 having an output shaft 11, the output shaft 11 being capable of forward and reverse rotation, the output shaft 11 having a first output end 111 and a second output end 112 disposed opposite to each other; a main brake mechanism 2 comprising a rotating transmission member 21, the rotating transmission member 21 and the output shaft 11 being parallel to each other and spaced apart, the rotating transmission member 21 having a first end 211 and a second end 212 disposed opposite to each other, the first end 211 of the rotating transmission member 21 being parallel to the output shaft 11 and spaced apart from each other, 11 is connected to the push rod through other transmission components of the drum brake system; the transmission mechanism 3 is connected between the output shaft 11 and the rotating transmission member 21. When the output shaft 11 rotates forward, it can drive the rotating transmission member 21 to move in the direction from its second end 212 to the first end 211. When the output shaft 11 rotates reversely, it can drive the rotating transmission member 21 to move in the direction from its first end 211 to the second end 212; the auxiliary braking mechanism 6 is connected to the second output end 112, and cooperates with the main braking mechanism 2 to achieve braking simultaneously or separately to further improve the braking effect and reliability.

[0052] The electronic mechanical actuator and drum brake system for drum brakes in the embodiment of the present application can drive the main brake mechanism 2 and / or the auxiliary brake mechanism 6 to operate through the transmission mechanism 3, thereby realizing the operation of the electronic mechanical actuator and drum brake system for drum brakes, wherein, when the output shaft 11 of the power mechanism 1 rotates forward, it can indirectly provide thrust to the push rod through other transmission components, and when the output shaft 11 of the power mechanism 1 reverses, it can provide pulling force to the push rod, thereby adjusting the braking state, and can effectively replace the pneumatic system in the existing drum brake system. Compared with the pneumatic system of the existing drum brake system, it has the effects of simple structure, small number of parts, small assembly space, easy maintenance and replacement, and reduced operating energy consumption.

[0053] like Figures 1 to 3 As shown, the present application provides an electromechanical actuator for a drum brake, which is connected to the push rod of the drum brake system. The electromechanical actuator for a drum brake includes a power mechanism 1, a main brake mechanism 2, a transmission mechanism 3, and an auxiliary brake mechanism 6. The power mechanism 1 is used to provide braking power, and the transmission mechanism 3 is used to transmit the braking power to the main brake mechanism 2 and / or the auxiliary brake mechanism 6. The main brake mechanism 2 and the auxiliary brake mechanism 6 convert the braking power according to the direction of force applied and transmit it to the vehicle's drum brake system to achieve braking of the vehicle. The auxiliary brake mechanism 6 can cooperate with the main brake mechanism 2 to achieve braking simultaneously or independently, further improving the braking effect and reliability.

[0054] The power mechanism 1 has an output shaft 11, which can rotate forward and reverse. Exemplarily, the power mechanism 1 is a motor.

[0055] The output shaft 11 has a first output end 111 and a second output end 112 that are arranged opposite to each other. In the embodiment of the present application, the power mechanism 1 is a double-headed motor.

[0056] The main brake mechanism 2 includes a rotating transmission member 21, which is parallel to and spaced from the output shaft 11. The rotating transmission member 21 has a first end 211 and a second end 212 that are opposite to each other. For example, the principle of the main brake mechanism 2 can be compared to a lead screw and nut structure, with the rotating transmission member 21 acting as a lead screw. Linear movement is achieved by axial translation of the rotating transmission member 21.

[0057] The first end 211 of the rotating transmission member 21 is connected to the push rod; optionally, the first end 211 of the rotating transmission member 21 is connected to the push rod through a double-ended fork 9, which is equivalent to extending the rotating transmission member 21 to achieve transmission of driving force, and the double-ended fork 9 can be replaced separately when damaged.

[0058] The transmission mechanism 3 is connected between the first output end 111 of the output shaft 11 and the rotating transmission member 21. When the output shaft 11 rotates forward, it can drive the rotating transmission member 21 to move in the direction from its second end 212 to the first end 211, providing thrust to the push rod. When the output shaft 11 is reversed, it can drive the rotating transmission member 21 to move in the direction from its first end 211 to the second end 212, providing pulling force to the push rod, thereby adjusting the braking state. It can effectively replace the pneumatic system in the existing drum brake system. Compared with the pneumatic system of the existing drum brake system, it has the effects of simple structure, small number of parts, small assembly space, easy maintenance and replacement, and reduced operating energy consumption.

[0059] For example, in the process of vehicle braking, the main brake mechanism 2 operates first, and by adjusting the rotation direction of the power mechanism 1, power is provided in a locked-rotor manner to achieve vehicle braking. When the vehicle decelerates and the vehicle speed is lower than a certain threshold, the auxiliary brake mechanism 6 is started to achieve the final stop and parking of the vehicle. After the auxiliary brake mechanism 6 is started, or after the vehicle stops and parks, the main brake mechanism 2 stops running to reduce unnecessary wear on the motor.

[0060] like Figure 2 As shown, the present application provides an electromechanical actuator for a drum brake, wherein the transmission mechanism 3 includes a driving gear 31 and a driven gear 32, the driving gear 31 is fixedly connected to the output shaft 11, the driven gear 32 is sleeved on the rotating transmission member 21, and the driven gear 32 is directly or indirectly screwed to the rotating transmission member 21, and the driving gear 31 and the driven gear 32 are meshed and connected.

[0061] The output shaft 11 drives the driving gear 31 to rotate synchronously, and the driving gear 31 drives the driven gear 32 to rotate. In the process of the driving gear 31 driving the driven gear 32 to rotate, since the position of the driven gear 32 along its axial direction remains unchanged, it can drive the rotating transmission member 21 to reciprocate along its axial direction, thereby realizing the linear movement of the rotating transmission member 21.

[0062] like Figures 2 to 4 As shown, the present application provides an electromechanical actuator for a drum brake, wherein the main brake mechanism 2 includes a sleeve 22, which is sleeved on a rotating transmission member 21. The rotating transmission member 21 has an external thread on at least a portion of its outer circumference, and an internal thread on its inner surface. The sleeve 22 is screwed to the external thread of the rotating transmission member 21 via the internal thread. The driven gear 32 is fixedly sleeved on the outside of the sleeve 22. In this embodiment of the present application, the sleeve 22 is equivalent to the nut in the screw-nut structure.

[0063] Optionally, a plurality of balls G are provided between the internal thread and the external thread, which can effectively improve the smoothness of the sleeve 22 rotating along the rotating transmission member 21 .

[0064] like Figures 2 to 4 As shown, the present application provides an electronic mechanical actuator for a drum brake, wherein a positioning groove 221 is recessed on the outer peripheral surface of the sleeve 22, and a tolerance ring 23 is fixedly embedded in the positioning groove 221. The tolerance ring 23 is embedded in the positioning groove 221 in an interference fit manner to fix the relative positions of the tolerance ring 23 and the sleeve 22.

[0065] The driven gear 32 is fixedly sleeved on the tolerance ring 23. Specifically, the driven gear 32 is sleeved and fixed on the outside of the tolerance ring 23 in an interference fit manner, which can effectively fix the sleeve 22, the tolerance ring 23 and the driven gear 32, ensuring that the three form a whole and move synchronously.

[0066] The outer peripheral surface of the tolerance ring 23 protrudes from the outer peripheral surface of the sleeve 22. In this way, when the driven gear 32 is assembled, the driven gear 32 can be smoothly assembled to the specified position of the rotating transmission member 21 along its axial direction, avoiding the situation where the driven gear 32 comes into contact with the surface of the rotating transmission member 21 before moving to the assembly position. It can effectively provide protection for the rotating transmission member 21 and prevent the surface of the rotating transmission member 21 from being scratched during the assembly of the driven gear 32, while reducing the difficulty of assembling the driven gear 32.

[0067] like Figure 1 and Figure 3 As shown, the present application provides an electromechanical actuator for a drum brake, wherein the electromechanical actuator for a drum brake has a housing, the housing including a first shell 4 and a second shell 5 that can be detachably connected, and the first shell 4 and the second shell 5 cooperate to form a cavity.

[0068] The transmission mechanism 3 is located inside the first housing 4, a portion of the power mechanism 1 is connected to the outside of the housing, and the output shaft 11 extends through the housing to the inside of the cavity and is connected to the transmission mechanism 3.

[0069] A portion of the main brake mechanism 2 is located inside the first shell 4 and is connected to the transmission mechanism 3. The first shell 4 can provide protection for the transmission connection position between the power mechanism 1 and the main brake mechanism 2, prevent external impurities from entering the transmission mechanism 3, and provide lubrication for the transmission connection position between the power mechanism 1 and the main brake mechanism 2, thereby improving the smoothness of the transmission.

[0070] The first end 211 of the rotary transmission member 21 extends through the first housing 4 to connect with a push rod of a vehicle drum brake system.

[0071] like Figure 2 and Figure 3 As shown, the present application provides an electronic mechanical actuator for a drum brake, wherein a bearing 24 is fixedly sleeved on the outer circumferential surface of the sleeve 22, a limiting groove S is recessed on the inner surface of the first shell 4 and / or the second shell 5, the bearing 24 is arranged in the limiting groove S, and the outer surface of the bearing 24 is clearance-matched with the groove wall of the limiting groove S; the bearing 24 can provide support and fixation for the main brake mechanism 2, prevent the main brake mechanism 2 from shaking inside the shell, and ensure that the main brake mechanism 2 runs smoothly and steadily.

[0072] A pressure ring 25 is also fixedly mounted on the outer circumference of the sleeve 22. The pressure ring 25 is positioned between the bearing 24 and the driven gear 32, and is spaced apart from the driven gear 32. The pressure ring 25 contacts the surface of the bearing 24 facing the driven gear 32. The pressure ring 25 serves to position the bearing 24 within the retaining groove S, preventing axial displacement of the bearing 24 during rotation of the rotary transmission member 21 and ensuring that the bearing 24 provides overall support for the main brake mechanism 2.

[0073] like Figure 4 As shown, the present application provides an electromechanical actuator for a drum brake, wherein, along the direction from the first end 211 to the second end 212 of the rotating transmission member 21, the rotating transmission member 21 includes a first section 213, a second section 214 and a third section 215 connected in sequence, and at least a portion of the first section 213 extends through to the outside of the first shell 4; the first section 213 and the third section 215 are optical axis sections, and an external thread is provided on the outer circumferential surface of the second end 212.

[0074] The electromechanical actuator for a drum brake also includes a second housing 5, which is connected to and internally communicates with the first housing 4. A portion of the second section 214 and the third section 215 extend through the first housing 4 and into the interior of the second housing 5. The second housing 5 cooperates with the first housing 4 to further protect the main brake mechanism 2, maximally confining the main brake mechanism 2 within a sealed space and preventing damage to the main brake mechanism 2 from external forces or damage to external components during operation.

[0075] Alternatively, as Figure 3 As shown, the limiting groove S may also be formed on the inner side of the second housing 5 , as long as the bearing 24 can be installed and limited.

[0076] like Figure 4 As shown, the present application provides an electromechanical actuator for a drum brake, wherein the third section 215 is provided with a limiting hole 2151 extending radially through the rotating transmission member 21. The limiting hole 2151 is a strip-shaped hole extending axially along the rotating transmission member 21. The main brake mechanism 2 also includes a limiting pin 26 extending radially through the limiting hole 2151 along the rotating transmission member 21, and the two ends of the limiting pin 26 are respectively connected to the second housing 5. By providing the limiting pin 26 extending through the rotating transmission member 21, the rotating transmission member 21 is effectively prevented from rotating with the driven gear 32. This ensures that when the driven gear 32 rotates, the rotating transmission member 21 inevitably moves axially, ensuring a smooth transition from rotation to linear motion. The strip-shaped limiting hole 2151 provides a buffer for the axial movement of the rotating transmission member 21, preventing the limiting pin 26 from interfering with the movement of the rotating transmission member 21.

[0077] like Figures 2 to 5 As shown, the electromechanical actuator for a drum brake provided by the present application has a guide ring 27 sleeved on the third section 215. Both ends of the limit pin 26 extend through the guide ring 27. The inner surface of the guide ring 27 is in sliding contact with the outer circumference of the third section 215, and the outer surface of the guide ring 27 is in sliding contact with the inner surface of the second housing 5. The guide ring 27 cooperates with the bearing 24 to guide the axial movement of the rotating transmission member 21, ensuring smooth movement of the rotating transmission member 21 and preventing movement jams caused by swinging of the rotating transmission member 21.

[0078] Optionally, the guide ring 27 is made of graphene material, which has good lubrication properties and can further improve the smoothness of the movement of the rotating transmission member 21.

[0079] like Figure 5As shown, the present application provides an electromechanical actuator for a drum brake, wherein a lubricating sleeve 28 is sleeved on the limit pin 26; during the movement of the rotating transmission member 21, when the limit pin 26 moves relative to the limit hole 2151, the friction between the limit pin 26 and the limit hole 2141 can be effectively reduced. Optionally, the lubricating sleeve 28 can also be made of graphene material.

[0080] like Figure 1 As shown, in the electromechanical actuator for a drum brake provided by the present application, both ends of the limit pin 26 respectively pass through the second housing 5, and a seal 29 is provided between the limit pin 26 and the second housing 5. The seal 29 can be directly provided on the outer surface of the second housing 5 to seal the through-connection between the limit pin 26 and the second housing 5.

[0081] like Figure 1 、 Figure 5 and Figure 6 As shown, the present application provides an electromechanical actuator for a drum brake, wherein the auxiliary braking mechanism includes a ratchet 61, a positioning pawl 62 and a magnetic component 63, the ratchet 61 is connected to the output shaft 11, and the output shaft 11 drives the ratchet 61 to rotate synchronously; the positioning pawl 62 is arranged on one side of the circumference of the ratchet 61, and the magnetic component 63 is connected to the positioning pawl 62, and the magnetic component 63 is used to drive the positioning pawl 62 to position or hook with the ratchet 61.

[0082] The electromechanical actuator for a drum brake further includes a third housing 7, which is detachably connected to the power mechanism 1. The second output terminal 112 and the auxiliary brake mechanism 6 are both disposed within the third housing 7. The positioning pawl 62 is rotatably connected to the third housing 7. The third housing 7 protects the auxiliary brake mechanism 6 and provides a mounting base for the positioning pawl 62.

[0083] like Figure 6 As shown in the figure, the electromechanical actuator for a drum brake provided by the present application includes a magnetic assembly 63 comprising a first magnet 631 and a second magnet 632. Both the first magnet 631 and the second magnet 632 are bistable electromagnets. When power is removed, they can maintain their current state without requiring continuous power. This characteristic makes bistable electromagnets very useful in many applications, significantly reducing energy consumption.

[0084] The second magnet 632 is mounted on the positioning pawl 62. The electromechanical actuator for a drum brake further includes a controller 8, which is disposed within the third housing 7 and is electrically connected to the power mechanism 1 and the first magnet 631. The controller 8 controls the power mechanism 1, enabling it to start and stop, thereby controlling the operation or stop of the main brake mechanism 2.

[0085] An embodiment of the present application further provides a drum brake system, wherein the drum brake system includes the electromechanical actuator for a drum brake as described above.

[0086] The drum brake system of the embodiment of the present application, wherein the power mechanism 1 of the electronic mechanical actuator for the drum brake can drive the main brake mechanism 2 to operate through the transmission mechanism 3, thereby driving the push rod movement of the drum brake system to realize the operation of the drum brake system, wherein, when the output shaft 11 of the power mechanism 1 rotates forward, it can provide thrust to the push rod, and when the output shaft 11 of the power mechanism 1 reverses, it can provide pulling force to the push rod, thereby adjusting the braking state, and can effectively replace the pneumatic system in the existing drum brake system. Compared with the pneumatic system of the existing drum brake system, it has the effects of simple structure, small number of parts, small assembly space, easy maintenance and replacement, and reduced operating energy consumption.

[0087] The above description is only a specific embodiment of the present application. Those skilled in the art will clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the scope of protection of the present application.

Claims

1. An electromechanical actuator for a drum brake, characterized in that: The electromechanical actuator for a drum brake comprises: A power mechanism (1) has an output shaft (11), the output shaft (11) can rotate forward and reverse, and the output shaft (11) has a first output end (111) and a second output end (112) arranged in opposite directions; A main brake mechanism (2) includes a rotating transmission member (21), wherein the rotating transmission member (21) and the output shaft (11) are parallel to each other and spaced apart, and the rotating transmission member (21) has a first end (211) and a second end (212) that are opposite to each other; A transmission mechanism (3) is connected between the first output end (111) and the rotating transmission member (21), and can drive the rotating transmission member (21) to move in a direction from its second end (212) to its first end (211) when the output shaft (11) rotates forward, and can drive the rotating transmission member (21) to move in a direction from its first end (211) to its second end (212) when the output shaft (11) rotates reversely; An auxiliary braking mechanism (6) is connected to the second output end (112).

2. The electromechanical actuator for a drum brake according to claim 1, characterized in that: The transmission mechanism (3) includes a driving gear (31) and a driven gear (32), wherein the driving gear (31) is fixedly connected to the output shaft (11), and the driven gear (32) is sleeved on the rotating transmission member (21), and the driven gear (32) is directly or indirectly screwed to the rotating transmission member (21), and the driving gear (31) and the driven gear (32) are meshed and connected; The output shaft (11) drives the driving gear (31) to rotate synchronously, and the driving gear (31) drives the driven gear (32) to rotate and rotate relative to the rotating transmission member (21) to drive the rotating transmission member (21) to reciprocate along its axial direction.

3. The electromechanical actuator for a drum brake according to claim 2, characterized in that: The main brake mechanism (2) comprises a sleeve (22), the sleeve (22) being sleeved and screwed onto the rotating transmission member (21); and the driven gear (32) being fixedly sleeved on the outside of the sleeve (22).

4. The electromechanical actuator for a drum brake according to claim 3, characterized in that: A positioning groove (221) is concavely provided on the outer circumferential surface of the sleeve (22), a tolerance ring (23) is fixedly embedded in the positioning groove (221), the outer circumferential surface of the tolerance ring (23) protrudes from the outer circumferential surface of the sleeve (22), and the driven gear (32) is fixedly sleeved on the tolerance ring (23).

5. The electromechanical actuator for a drum brake according to claim 3, characterized in that: The electromechanical actuator for a drum brake has a housing, the housing comprising a first shell (4) and a second shell (5) that are detachably connected, the first shell and the second shell cooperating to form a cavity; The transmission mechanism (3) is located inside the cavity; A portion of the power mechanism (1) is disposed outside the housing, and the output shaft (11) passes through the housing and extends into the cavity to connect with the transmission mechanism; A portion of the main brake mechanism (2) is located inside the first housing (4) and connected to the transmission mechanism (3), and the first end (211) of the rotating transmission member (21) extends through and out of the first housing (4).

6. The electromechanical actuator for a drum brake according to claim 5, characterized in that: A bearing (24) is fixedly sleeved on the outer circumferential surface of the sleeve (22); a limiting groove (S) is recessed on the inner surface of the first shell (4) and / or the second shell (5); the bearing (24) is arranged in the limiting groove (S); and the outer surface of the bearing (24) is clearance-matched with the groove wall of the limiting groove (S); A pressure ring (25) is fixedly sleeved on the outer peripheral surface of the sleeve (22). The pressure ring (25) is located between the bearing (24) and the driven gear (32). The pressure ring (25) and the driven gear (32) are spaced apart. The pressure ring (25) contacts the surface of the bearing facing the driven gear.

7. The electromechanical actuator for a drum brake according to claim 6, characterized in that: Along the direction from the first end (211) to the second end (212) of the rotating transmission member (21), the rotating transmission member (21) includes a first section (213), a second section (214), and a third section (215) connected in sequence, and at least a portion of the first section (213) extends through to the outside of the first housing (4); The electromechanical actuator for a drum brake further comprises a second housing (5), wherein the second housing (5) is communicated with the first housing (4), and a portion of the second section (214) and the third section (215) penetrate the first housing (4) and extend into the interior of the second housing (5).

8. The electromechanical actuator for a drum brake according to claim 7, characterized in that: The third section (215) is provided with a limiting hole (2151) penetrating along the radial direction of the rotating transmission member (21), and the limiting hole (2151) is a strip-shaped hole extending along the axial direction of the rotating transmission member (21); The main brake mechanism (2) further comprises a limiting pin (26), the limiting pin (26) passing through the limiting hole (2151) along the radial direction of the rotating transmission member (21), and both ends of the limiting pin (26) are respectively connected to the second housing (5).

9. The electromechanical actuator for a drum brake according to claim 8, characterized in that The third section (215) is sleeved with a guide ring (27), and both ends of the limit pin (26) pass through the guide ring (27) respectively. The inner surface of the guide ring (27) is in sliding contact with the outer peripheral surface of the third section (215), and the outer surface of the guide ring (27) is in sliding contact with the inner surface of the second shell (5).

10. The electromechanical actuator for a drum brake according to claim 8 or 9, characterized in that: The limiting pin shaft (26) is sleeved with a lubricating sleeve (28); And / or, both ends of the limiting pin shaft (26) respectively pass through the second shell (5), and a sealing member (29) is provided between the limiting pin shaft (26) and the second shell (5).

11. The electromechanical actuator for a drum brake according to claim 1, characterized in that The auxiliary braking mechanism is a power-loss brake.

12. The electromechanical actuator for a drum brake according to claim 11, characterized in that: The auxiliary braking mechanism (6) comprises a ratchet (61), a positioning pawl (62) and a magnetic component (63); the ratchet (61) is connected to the output shaft (11); the output shaft (11) drives the ratchet (61) to rotate synchronously; the positioning pawl (62) is arranged on one side of the circumference of the ratchet (61); the magnetic component (63) is connected to the positioning pawl (62); the magnetic component (63) is used to drive the positioning pawl (62) to be positioned and hooked or separated from the ratchet (61).

13. The electromechanical actuator for a drum brake according to claim 12, characterized in that: The electromechanical actuator for a drum brake further comprises a third housing (7), the third housing (7) being detachably connected to the power mechanism (1), the second output end (112) and the auxiliary brake mechanism (6) being both arranged inside the third housing (7), and the positioning pawl (62) being rotatably connected to the third housing (7).

14. The electromechanical actuator for a drum brake according to claim 13, characterized in that: The magnetic component (63) includes a first magnet (631) and a second magnet (632), and both the first magnet and the second magnet are bistable electromagnets; The second magnet (632) is mounted on the positioning pawl (62); The electromechanical actuator for a drum brake further comprises a controller (8), wherein the controller (8) is arranged inside the third housing (7), and the controller (8) is electrically connected to the power mechanism (1) and the first magnet (631) respectively.

15. A drum brake system, characterized in that: The drum brake system includes the electromechanical actuator for a drum brake according to any one of claims 1 to 14.

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