Electronic parking drum brake device

Abstract

The invention provides an electronic parking drum brake device. The electronic parking drum brake device is characterized in that a parking hub with an inner cavity is connected with a tail shaft of a hub motor; the parking mechanism is positioned in the inner cavity; the driving mechanism is located in the inner cavity, the elastic structure is connected between the first friction part and the second friction part, the locking structure is provided with a pushing assembly and a driving assembly, the first end and the second end which are opposite abut against the first friction part and the second friction part respectively, and the driving assembly is connected with the pushing assembly and can drive the pushing assembly to rotate; when the first end and the second end move to a first relative position in the direction away from each other, the first end and the second end push the first friction part and the second friction part to abut against the inner walls of the two opposite sides of the parking hub respectively. When the first end and the second end move to the second relative position in the approaching direction, the elastic structure pulls the first friction part and the second friction part to be separated from the inner walls of the two opposite sides of the parking hub correspondingly, and the problem that a drum type EPB brake affects the layout of a hub motor automobile chassis is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle brake equipment, and in particular to an electronic parking drum brake device. Background Art

[0002] The description in this section merely provides background information related to the present disclosure and does not constitute prior art.

[0003] With the depletion of fossil energy and the aggravation of air pollution, new energy electric vehicles are receiving more and more attention from the society. Electric vehicles include hybrid vehicles, fuel cell vehicles, pure electric vehicles, etc. They are energy-saving and environmentally friendly, and are the development direction of the new generation of automobile technology. Among all electric vehicle configuration schemes, the scheme that directly integrates the motor with the wheel is called wheel hub motor drive. Wheel hub motor drive technology is a key technology to improve the performance of electric vehicles. It has obvious advantages: on the one hand, it can replace the traditional powertrain, simplify the chassis structure, and realize the flexible layout of the whole vehicle; at the same time, it can realize independent control of each wheel and real-time full drive, without the need to comprehensively control the vehicle power transmission system and braking system like traditional vehicles to realize wheel driving force control; thirdly, wheel hub motor drive greatly improves transmission efficiency, thereby improving the energy saving and power of the vehicle, and can achieve better performance of automobile chassis control technology at a lower cost.

[0004] In order to make the wheel hub motor drive structure more compact, practical, safe and reliable, the choice of brakes is particularly important. Automobile brakes are mainly divided into drum brakes and disc brakes. Drum brakes have a compact structure, low driving drag torque, small axial space occupancy, large braking torque, and low manufacturing cost, but poor heat dissipation capacity, and need to be equipped with a cable brake structure to realize the parking brake function. Therefore, drum brakes are generally installed on the rear wheels of the car, and it is rare to install four drum brakes on the four wheel hubs of the car. In contrast, disc brakes have good heat dissipation capacity, and disc brakes are easier to integrate EPB electronic parking functions. Therefore, on the four-wheel drive models of traditional cars, due to the ample wheel side space, it is naturally easy to choose to install the disc brakes that realize the EPB function on the four wheel hubs of traditional cars. In the design process of existing electric vehicles, comprehensive consideration of heat dissipation and the use of mature product designs is usually adopted. The disc brakes with EPB functions are installed on the four wheel hubs of electric vehicles.

[0005] Based on the above background, disc brakes have a complex structure and relatively high manufacturing costs. They are difficult to achieve low drag torque and have a high axial space occupation. In particular, disc brakes with integrated EPB electronic parking function have an axial length that is much longer than disc brakes of the same size without EPB function. Therefore, in the drive structure of the electric vehicle's hub motor, which has high requirements for the axial space on the wheel side, the layout of the disc EPB brake will undoubtedly increase the axial length of the overall structure and increase the weight of the drive mechanism. In addition, the disc EPB brake occupies the chassis space of the electric vehicle. If the disc EPB brake is replaced with a drum EPB brake, there are also certain problems. The main structure of the drum EPB brake only uses an electric drive cable mechanism to replace the parking drive device of the hand-pull parking mechanism. The cable mechanism of the drum EPB brake is external. In addition to the brake oil pipe, there is also a long cable connecting the brake, which will also affect the overall layout of the electric vehicle chassis.

[0006] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0007] The purpose of the present invention is to provide an electronic parking drum brake device, which solves the problem that the drum EPB brake affects the layout of the chassis of a hub motor vehicle.

[0008] The above-mentioned implementation objectives of the present invention are mainly achieved by the following technical solutions:

[0009] The present invention provides an electronic parking drum brake device, comprising:

[0010] A parking hub having an inner cavity, the parking hub being connected to a tail shaft of the wheel hub motor;

[0011] a parking mechanism located in the inner cavity, the parking mechanism comprising a first friction portion and a second friction portion;

[0012] A driving mechanism located in the inner cavity, the driving mechanism comprising a locking structure and an elastic structure, the elastic structure being connected between the first friction part and the second friction part, the locking structure comprising a pushing component and a driving component, the pushing component comprising a first end and a second end opposite to each other, the first end and the second end respectively abutting against the first friction part and the second friction part, the driving component being connected to the pushing component, and the driving component being able to drive the pushing component to rotate so as to move the first end and the second end in a direction away from or close to each other;

[0013] When the first end and the second end move away from each other to a first relative position, the first end and the second end respectively push the first friction portion and the second friction portion to abut against inner walls on two opposite sides of the parking hub;

[0014] When the first end and the second end move toward each other to a second relative position, the elastic structure pulls the first friction portion and the second friction portion to be separated from the inner walls on two opposite sides of the parking hub.

[0015] In a specific embodiment,

[0016] The axis of the parking hub and the axis of the tail shaft are located in the same straight line. The parking hub has a first axial end and a second axial end opposite to each other along its own axis, the first axial end is close to the tail shaft, and the second axial end is far away from the tail shaft. The first axial end is formed with a connecting hole portion extending toward the inner cavity along the rotation axis of the tail shaft, and the parking hub is connected to the tail shaft of the wheel hub motor through the connecting hole portion so that the parking hub can rotate synchronously with the tail shaft.

[0017] In a specific embodiment,

[0018] The electronic parking drum brake device further includes an end cover, which is formed at the second axial end. The end cover has a connecting wall facing the inner cavity, and the parking mechanism and the driving mechanism are respectively connected to the connecting wall.

[0019] In a specific embodiment,

[0020] The first friction part and the second friction part are both arc-shaped structures that can fit with the inner wall of the parking hub, and one end of the first friction part is disposed adjacent to one end of the second friction part and is rotatably connected to the end cover through a first rotating shaft and a second rotating shaft respectively;

[0021] The other end of the first friction portion and the other end of the second friction portion can swing around the first rotation axis and the second rotation axis respectively toward a direction close to or away from the inner wall of the parking hub.

[0022] In a specific embodiment,

[0023] The elastic structure includes at least one elastic member, wherein the at least one elastic member is connected between the other end of the first friction portion and the other end of the second friction portion.

[0024] In a specific embodiment,

[0025] The pushing assembly includes a pushing shaft, the axis of the pushing shaft is arranged parallel to the axis of the elastic member, the first end and the second end are respectively connected to the two ends of the pushing shaft by threads, and the driving assembly can drive the pushing shaft to rotate so that the first end and the second end can be respectively retracted or rotated out relative to the two ends of the pushing shaft.

[0026] In a specific embodiment,

[0027] The driving assembly includes a driving member, and the pushing assembly also includes a worm wheel and a worm member, wherein the driving member has an output tooth portion that can rotate around its own axis, and the worm member has a spiral tooth portion and an input tooth portion spaced apart along its own axial direction, and the worm wheel is sleeved on the pushing shaft;

[0028] Among them, the output tooth portion is meshed and connected with the input tooth portion, so that the driving member can drive the worm member to rotate around its own axis; the spiral tooth portion is meshed and connected with the worm wheel, so that the worm member can drive the worm wheel to rotate and drive the driving shaft to rotate around its own axis.

[0029] In a specific embodiment,

[0030] The driving member and the worm member are both extended toward the inner side of the parking hub in a direction perpendicular to the axis of the driving shaft, the spiral tooth portion of the worm member is arranged close to the tail shaft, and the input tooth portion is arranged away from the tail shaft.

[0031] In a specific embodiment,

[0032] The worm wheel has a clamping hole, the axis of the clamping hole and the axis of the worm wheel are located on the same straight line, the worm wheel is movably mounted on the driving shaft through the clamping hole, a clamping portion is formed on the outer side of the driving shaft, the worm wheel is clamped with the clamping portion through the clamping hole, and the worm wheel can drive the driving shaft to rotate along its own axis.

[0033] In a specific embodiment,

[0034] There are two drive assemblies, which are respectively arranged on opposite sides of the connecting hole portion. The drive members of the two drive assemblies are respectively meshed and connected with opposite sides of the input tooth portion of the worm member through the output tooth portion, so as to synchronously drive the worm member to rotate.

[0035] In a specific embodiment,

[0036] The drive assembly also includes a deceleration rod member, which is arranged between the drive member and the worm member, and extends toward the inner side of the parking hub in a direction perpendicular to the axis of the driving shaft. The deceleration rod member has a first deceleration tooth portion and a second deceleration tooth portion arranged at intervals along its own axial direction, and the first deceleration tooth portion and the second deceleration tooth portion are respectively meshed and connected with the output tooth portion and the input tooth portion, wherein the diameter of the first deceleration tooth portion is larger than the diameter of the output tooth portion, so as to increase the output torque of the drive member; the diameter of the second deceleration tooth portion is smaller than the diameter of the input tooth portion, so as to increase the transmission torque of the deceleration rod member.

[0037] In a specific embodiment,

[0038] The parking mechanism also includes a plurality of axial positioning springs, which are extended along the axial direction of the parking hub, one end of each of the axial positioning springs is connected to the end cover, and the other end of each of the axial positioning springs is respectively abutted against the first friction portion or the second friction portion in the axial direction of the axial positioning springs toward the end cover, so as to pull the first friction portion or the second friction portion to abut against the end cover.

[0039] Compared with the prior art, the technical solution of the present invention has the following characteristics and advantages:

[0040] The electronic parking drum brake device provided by the present invention solves the problem that the arrangement space of the highly integrated wheel hub motor service brake is limited and the electronic parking function cannot be integrated, and a parking brake needs to be added to realize the automatic parking function. A parking hub is provided to be installed on the tail shaft end of the wheel hub motor, and a parking mechanism and a driving mechanism are arranged in the inner cavity of the parking hub, so that the electronic parking drum brake device is small in size. Compared with the disc EPB (Electrical Park Brake, EPB), the axial length of the electronic parking drum brake device is greatly shortened, and it can be integrated on the end cover of the tail shaft of the wheel hub motor, and the braking force is large.

[0041] The electronic parking drum brake device provided by the present invention is usually only responsible for parking braking. In an emergency, it can also serve as an emergency driving braking unit through the comprehensive control of the existing electronically controlled brake device of the electric vehicle, thereby improving the emergency braking capability and driving safety capability of the existing electric vehicles.

[0042] The electronic parking drum brake device provided by the present invention can achieve a drag torque of 0 N·m after releasing the brake on the wheel hub, and will not affect the working efficiency of the wheel hub motor under normal driving conditions of the electric vehicle. That is, the electronic parking drum brake device provided by the present invention is basically free of wear when the wheel hub motor works normally, and can be basically maintenance-free.

[0043] Compared with the traditional drum EPB (Electrical Park Brake, EPB), the electronic parking drum brake device provided by the present invention has a driving mechanism for driving the movement of the parking mechanism that is completely integrated inside the parking hub, eliminating the electric-driven cable structure arranged outside the parking hub, avoiding the problems of cable sleeve bending and suspension swinging that need to be considered in the layout of the cable, and achieving a high degree of integration and electronic control.

[0044] The electronic parking drum brake device provided by the present invention respectively pushes the first friction part and the second friction part to abut against the parking hub through the relatively arranged first end and the second end, thereby realizing synchronous control of the first friction part and the second friction part to abut against the inner wall of the parking hub, and can provide a more stable braking effect, avoiding the risk of reduced braking effect due to asynchronous abutment between the first friction part and the second friction part and the inner wall of the parking hub. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a structural diagram of the electronic parking drum brake device of the present invention;

[0046] Figure 2 An exploded structural diagram of the electronic parking drum brake device of the present invention;

[0047] Figure 3 is a structural diagram of a driving mechanism of an electronic parking drum brake device of the present invention;

[0048] Figure 4 The exploded structural diagram of the driving mechanism of the electronic parking drum brake device of the present invention.

[0049] Description of Figure Numbers:

[0050] 100, parking hub; 110, first axial end; 1101, connecting hole portion; 120, second axial end;

[0051] 200, parking mechanism; 210, first friction part; 220, second friction part;

[0052] 230. Axial positioning spring; 231. Stopper;

[0053] 241, connecting layer; 242, friction layer;

[0054] 300, driving mechanism;

[0055] 310. Locking structure;

[0056] 311, push component;

[0057] 3111, driving shaft; 3112, first end; 3113, second end; 3114, clamping portion;

[0058] 3115, worm gear; 3116, snap-on hole;

[0059] 3117, worm gear; 3118, spiral gear portion; 3119, input gear portion;

[0060] 312. Drive assembly;

[0061] 3121, driving member; 3122, output gear portion;

[0062] 3123, a deceleration rod; 3124, a first deceleration tooth portion; 3125, a second deceleration tooth portion;

[0063] 320. elastic structure; 321. elastic member;

[0064] 400, end cover; 410, connecting wall;

[0065] 420, first rotating shaft; 430, second rotating shaft;

[0066] A. Inner cavity. DETAILED DESCRIPTION

[0067] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. 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 creative work should fall within the scope of protection of the present invention.

[0068] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0070] like Figures 1 to 4 As shown, the present invention provides an electronic parking drum brake device, comprising:

[0071] A parking hub 100 having an inner cavity A, the parking hub 100 being connected to the tail shaft of the wheel hub motor;

[0072] A parking mechanism 200 located in the inner cavity A, the parking mechanism 200 comprising a first friction portion 210 and a second friction portion 220;

[0073] The driving mechanism 300 is located in the inner cavity A. The driving mechanism 300 includes a locking structure 310 and an elastic structure 320. The elastic structure 320 is connected between the first friction part 210 and the second friction part 220. The locking structure 310 has a pushing component 311 and a driving component 312. The pushing component 311 has a first end 3112 and a second end 3113 opposite to each other. The first end 3112 and the second end 3113 are respectively against the first friction part 210 and the second friction part 220, that is, the first end 3112 is against the first friction part 210, and the second end 3113 is against the second friction part 220. The driving component 312 is connected to the pushing component 311, and the driving component 312 can drive the pushing component 311 to rotate, so that the first end 3112 and the second end 3113 move in a direction away from or close to each other.

[0074] When the first end 3112 and the second end 3113 move away from each other to the first relative position, the first end 3112 and the second end 3113 respectively push the first friction portion 210 and the second friction portion 220 to abut against the inner walls of the two opposite sides of the parking hub 100;

[0075] When the first end 3112 and the second end 3113 move toward each other to the second relative position, the elastic structure 320 pulls the first friction portion 210 and the second friction portion 220 to separate from the inner walls of the two opposite sides of the parking hub 100 .

[0076] When the first friction portion 210 and the second friction portion 220 respectively abut against the inner walls of two opposite sides of the parking hub 100 , the position of the first end 3112 relative to the second end 3113 (or the second end 3113 relative to the first end 3112 ) is the first relative position.

[0077] Among them, when the first friction portion 210 and the second friction portion 220 are respectively separated from the inner walls on the two opposite sides of the parking hub 100, the position of the first end 3112 relative to the second end 3113 (or the second end 3113 relative to the first end 3112) is the second relative position. At this time, the specific position of the first end 3112 and the specific position of the second end 3113 are not limited. It is only required that the first friction portion 210 does not abut against the inner wall of the parking hub 100, and the second friction portion 220 does not abut against the inner wall of the parking hub 100. In this state, any position of the first end 3112 relative to the second end 3113 (or the second end 3113 relative to the first end 3112) can be considered as the second relative position.

[0078] The electronic parking drum brake device provided by the present invention solves the problem that the arrangement space of the highly integrated hub motor service brake is limited and the electronic parking function cannot be integrated, and a parking brake needs to be added to realize the automatic parking function. A parking hub 100 is provided to be installed on the tail shaft end of the hub motor, and a parking mechanism 200 and a driving mechanism 300 are arranged in the inner cavity A of the parking hub 100, so that the electronic parking drum brake device is small in size. Compared with the disc EPB (Electrical Park Brake, EPB), the axial length of the electronic parking drum brake device is greatly shortened, and it can be integrated on the tail shaft end of the hub motor, and has a large braking force.

[0079] The electronic parking drum brake device provided by the present invention is usually only responsible for parking braking. In an emergency, it can also serve as an emergency driving braking unit through the comprehensive control of the existing electronically controlled brake device of the electric vehicle, thereby improving the emergency braking capability and driving safety capability of the existing electric vehicles.

[0080] The electronic parking drum brake device provided by the present invention can achieve a drag torque of 0 N·m after releasing the brake on the wheel hub, and will not affect the working efficiency of the wheel hub motor under normal driving conditions of the electric vehicle. That is, the electronic parking drum brake device provided by the present invention is basically free of wear when the wheel hub motor works normally, and can basically achieve maintenance-free or less frequent maintenance.

[0081] Compared with the traditional drum EPB (Electrical Park Brake, EPB), the electronic parking drum brake device provided by the present invention has a driving mechanism 300 that drives the parking mechanism 200 to move, which is completely integrated inside the parking hub 100, eliminating the electrically driven cable structure arranged outside the parking hub 100, avoiding the problems of cable sleeve bending and suspension swinging that need to be considered in the layout of the cable, and achieving a high degree of integration and electronic control.

[0082] The electronic parking drum brake device provided by the present invention respectively pushes the first friction portion 210 and the second friction portion 220 to abut against the parking hub 100 through the relatively arranged first end 3112 and the second end 3113, that is, the first end 3112 pushes the first friction portion 210 to abut against the parking hub 100, and the second end 3113 pushes the second friction portion 220 to abut against the parking hub 100, thereby achieving synchronous control of the first friction portion 210 and the second friction portion 220 to abut against the inner wall of the parking hub 100, which can provide a more stable braking effect and avoid the risk of reduced braking effect due to asynchronous abutment between the first friction portion 210 and the second friction portion 220 and the inner wall of the parking hub 100.

[0083] Specifically in this embodiment, the parking hub 100 is generally cylindrical, and the axis of the parking hub 100 and the axis of the tail shaft of the hub motor are located on the same straight line, that is, the parking hub 100 and the tail shaft of the hub motor rotate synchronously at the same angular velocity, and the first friction portion 210 and the second friction portion 220 are connected to the end cover 400 of the hub motor. When the first friction portion 210 and the second friction portion 220 are respectively in contact with the inner wall of the parking hub 100, the parking stop or braking of the tail shaft of the hub motor is achieved through the static friction between the first friction portion 210 or the second friction portion 220 and the inner wall of the parking hub 100.

[0084] In this embodiment, the first friction portion 210 and the second friction portion 220 are generally composed of two stacked structures, one of which is a connecting layer 241 facing the inside of the parking hub 100, and the other is a friction layer 242 facing the inner wall of the parking hub 100. The friction layer 242 is stacked on the connecting layer 241 and fixedly connected to the connecting layer 241. The friction layer 242 is used to rub against the inner wall of the parking hub 100, and the connecting layer 241 is used to connect with the locking structure 310 and the elastic structure 320, wherein the elastic structure 320 is connected between the connecting layer 241 of the first friction portion 210 and the connecting layer 241 of the second friction portion 220, and the locking structure 310 is arranged between the connecting layer 241 of the first friction portion 210 and the connecting layer 241 of the second friction portion 220, and the first end 3112 and the second end 3113 of the pushing component 311 of the locking structure 310 are respectively abutted against the connecting layer 241 of the first friction portion 210 and the connecting layer 241 of the second friction portion 220.

[0085] Related References Figure 4As shown, in this embodiment, the driving mechanism 300 includes a locking structure 310 and an elastic structure 320. The locking structure 310 is used to push the first friction portion 210 and the second friction portion 220 of the parking mechanism 200 to resist the inner wall of the parking hub 100 to achieve the purpose of parking stop locking. The elastic structure 320 is connected between the first friction portion 210 and the second friction portion 220 to pull the first friction portion 210 and the second friction portion 220 closer to each other, that is, to pull the first friction portion 210 and the second friction portion 220 away from the inner wall of the parking hub 100 to achieve the purpose of unlocking the parking.

[0086] In the present embodiment, the elastic structure 320 generally has two ends that contract toward each other, and the two ends of the elastic structure 320 are respectively connected to the connecting layer 241 of the first friction portion 210 and the connecting layer 241 of the second friction portion 220, that is, one end of the elastic structure 320 is connected to the connecting layer 241 of the first friction portion 210, and the other end of the elastic structure 320 is connected to the connecting layer 241 of the second friction portion 220, so as to pull the first friction portion 210 and the second friction portion 220 to separate from the inner walls on the opposite sides of the parking hub 100. The elastic structure 320 in the present embodiment is a single spring. In other embodiments, the elastic structure 320 can also be a combination structure of multiple springs, and there is no specific restriction on the specific structural form of the elastic structure 320.

[0087] In this embodiment, the locking structure 310 includes a driving assembly 312. The driving assembly 312 in this embodiment is a single motor with an output shaft. In other embodiments, the driving assembly 312 may also include multiple motors arranged in parallel, and there is no specific limitation on this.

[0088] In this embodiment, the locking structure 310 includes a pushing component 311, and the pushing component 311 has a pushing shaft 3111 that can be set along the axial direction of the spring of the elastic structure 320. The first end 3112 and the second end 3113 are respectively set at the two ends of the pushing shaft 3111. In this embodiment, the first end 3112 and the second end 3113 are provided with a stop shape that cooperates with the external shell of the driving mechanism 300. The stop shape can abut against the external shell along the axial direction of the pushing shaft 3111 to limit the movement range of the first end 3112 on the pushing shaft 3111 to prevent the first end 3112 from rotating to separate from the pushing shaft 3111. The stop shape can abut against the external shell along the axial direction of the pushing shaft 3111 to limit the movement range of the second end 3113 on the pushing shaft 3111 to prevent the second end 3113 from rotating to separate from the pushing shaft 3111. The stop shape is used to cooperate with the rotation of the pushing shaft 3111 and thereby Screw out and screw in; in other embodiments, the setting direction of the pushing shaft 3111 is not limited; in this embodiment, the pushing component 311 is meshed and connected with the driving component 312. In other embodiments, the pushing component 311 can also be connected to the driving component 312 in other forms of transmission; in this embodiment, the first end 3112 and the second end 3113 of the pushing component 311 are respectively against the connecting layer 241 of the first friction part 210 and the connecting layer 241 of the second friction part 220, that is, the first end 3112 is against the first friction part 210, and the second end 3113 is against the second friction part 220. The driving component 312 can drive the pushing component 311 to rotate through the transmission relationship with the pushing component 311, so that the first end 3112 and the second end 3113 move in a direction away from or close to each other. In this embodiment, the moving axis of the first end 3112 and the moving axis of the second end 3113 are located on the same straight line.

[0089] In this embodiment, when the first friction portion 210 and the second friction portion 220 respectively abut against the inner walls of two opposite sides of the parking hub 100, the position of the first end 3112 relative to the second end 3113 (or the second end 3113 relative to the first end 3112) is the first relative position.

[0090] In this embodiment, when the first end 3112 and the second end 3113 are moving away from each other, when the first end 3112 and the second end 3113 are both moved to the first relative position, the first friction portion 210 and the second friction portion 220 move in the direction away from each other to the positions where they abut against the inner walls on the two opposite sides of the parking hub 100, thereby achieving the stopping and parking of the electric vehicle.

[0091] In this embodiment, when the first friction portion 210 and the second friction portion 220 are respectively separated from the inner walls on two opposite sides of the parking hub 100, the position of the first end 3112 relative to the second end 3113 (or the second end 3113 relative to the first end 3112) is the second relative position. At this time, the specific position of the first end 3112 and the specific position of the second end 3113 are not limited. It is only required that the first friction portion 210 does not abut against the inner wall of the parking hub 100, and the second friction portion 220 does not abut against the inner wall of the parking hub 100. In this state, any position of the first end 3112 relative to the second end 3113 (or the second end 3113 relative to the first end 3112) can be considered as the second relative position.

[0092] In this embodiment, when the first end 3112 and the second end 3113 are moving closer to each other, when the first end 3112 and the second end 3113 are both moved to the second relative position, the first friction portion 210 and the second friction portion 220 move in the approaching direction to positions separated from the inner walls on the two opposite sides of the parking hub 100, respectively, to achieve the effect of unlocking the parking, that is, to unlock the electronic parking of the electric vehicle.

[0093] like Figure 1 and Figure 2 As shown, in one specific embodiment,

[0094] The axis of the parking hub 100 is located in the same straight line as the axis of the tail shaft. The parking hub 100 has a first axial end 110 and a second axial end 120 which are opposite to each other along its own axis. The first axial end 110 is close to the tail shaft, and the second axial end 120 is far away from the tail shaft. The first axial end 110 is formed with a connecting hole portion 1101 extending toward the inner cavity A along the rotation axis of the tail shaft. The parking hub 100 is connected to the tail shaft of the wheel hub motor through the connecting hole portion 1101 so that the parking hub 100 can rotate synchronously with the tail shaft.

[0095] In the electronic parking drum brake device provided by the present invention, the axis of the parking hub 100 and the axis of the tail shaft are located in the same straight line, that is, the parking hub 100 rotates synchronously with the tail shaft. In this embodiment, the parking hub 100 is generally cylindrical, and a first axial end 110 and a second axial end 120 are formed at two ends located on the axis of the parking hub 100. The connecting hole portion 1101 formed on the first axial end 110 is generally a connecting hole portion 1101 with an inner wall extending inward from the end surface of the parking hub 100. In this embodiment, the cross-section of the connecting hole portion 1101 is in a spline shape for connecting to the spline of the tail shaft. In other embodiments, the cross-section of the inner wall of the connecting hole portion 1101 can also be set to other shapes for connection; in this embodiment, the parking hub 100 is sleeved on the tail shaft through the connecting hole portion 1101 for synchronous rotation with the tail shaft.

[0096] like Figure 1 and Figure 2 As shown, in one specific embodiment,

[0097] The electronic parking drum brake device further includes an end cover 400 , which is formed at the second axial end 120 . The end cover 400 has a connecting wall 410 facing the inner cavity A, and the parking mechanism 200 and the driving mechanism 300 are respectively connected to the connecting wall 410 .

[0098] Specifically in the present embodiment, the end cover 400 is generally in the shape of a disc. In other embodiments, the specific shape of the end cover 400 is not limited. In the present embodiment, the second axial end 120 of the parking hub 100 is formed with an opening, and the opening is oriented along the axial direction of the parking hub 100. In the present embodiment, the end cover 400 is extended from the tail shaft cover of the hub motor, and the end cover 400 is formed at the opening of the second axial end 120 of the parking hub 100. The end cover 400 has a connecting wall 410 facing the inner cavity A of the parking hub 100.

[0099] In this embodiment, the first friction portion 210 and the second friction portion 220 of the parking mechanism 200 are movably connected to the connecting wall 410, and the friction forces generated by the first friction portion 210 and the second friction portion 220 respectively abutting against the inner walls on two opposite sides of the parking hub 100 are transmitted to the end cover 400 through the connection relationship between the first friction portion 210 and the end cover 400 and the connection relationship between the second friction portion 220 and the end cover 400.

[0100] In this embodiment, the pushing component 311 and the driving component 312 of the locking structure 310 of the driving mechanism 300 are respectively connected to the connecting wall 410, so as to drive the first end 3112 and the second end 3113 of the pushing component 311 to move away from each other through the driving component 312, thereby achieving the parking stop effect, thereby avoiding the problem of being unable to achieve the stopping effect due to connecting the pushing component 311 and the driving component 312 of the driving mechanism 300, the first friction portion 210, and the second friction portion 220 of the parking mechanism 200 to the parking hub 100.

[0101] like Figure 2 As shown, in one specific embodiment,

[0102] The first friction part 210 and the second friction part 220 are both arc-shaped structures that can fit with the inner wall of the parking hub 100. One end of the first friction part 210 is disposed adjacent to one end of the second friction part 220 and is rotatably connected to the end cover 400 through the first rotating shaft 420 and the second rotating shaft 430 respectively.

[0103] The other end of the first friction portion 210 and the other end of the second friction portion 220 can swing around the first rotation shaft 420 and the second rotation shaft 430 respectively toward a direction close to or away from the inner wall of the parking hub 100 .

[0104] The electronic parking drum brake device provided by the present invention, by configuring the first friction portion 210 and the second friction portion 220 to be an arc structure that fits the inner wall of the parking hub 100, when the first friction portion 210 and the second friction portion 220 abut against the inner walls of the two opposite sides of the parking hub 100, the arc structure can significantly increase the contact area between the first friction portion 210 and the inner wall of the parking hub 100, and increase the contact area between the second friction portion 220 and the inner wall of the parking hub 100, thereby improving the stopping parking effect of the first friction portion 210 and the second friction portion 220 on the parking hub 100.

[0105] Related References Figure 2 As shown, specifically in the present embodiment, one end of the first friction portion 210 is rotatably connected to the end cover 400 via the first rotating shaft 420, and the other end of the first friction portion 210 can swing around the axis of the first rotating shaft 420 via the end of the first friction portion 210 connected to the first rotating shaft 420. In the present embodiment, the first friction portion 210 can swing around the axis of the first rotating shaft 420 toward the inner wall of the parking hub 100 or toward the inner wall of the parking hub 100.

[0106] In this embodiment, one end of the second friction portion 220 is rotatably connected to the end cover 400 via the second rotating shaft 430, and the other end of the second friction portion 220 can swing around the axis of the second rotating shaft 430 through the end connected to the second rotating shaft 430 through the second friction portion 220. In this embodiment, the second friction portion 220 can swing around the axis of the second rotating shaft 430 toward the inner wall of the parking hub 100 or toward the inner wall of the parking hub 100.

[0107] In the present embodiment, the first friction portion 210 and the second friction portion 220 can respectively swing toward the direction close to the inner wall of the parking hub 100 and respectively abut against the inner walls on two opposite sides of the parking hub 100. In the present embodiment, the first rotating shaft 420 and the second rotating shaft 430 are arranged on the end cover 400, and the axis of the first rotating shaft 420 is oriented toward the axis of the second rotating shaft 430. In the present embodiment, one end of the first friction portion 210 is adjacent to one end of the second friction portion 220, that is, the first rotating shaft 420 and the second rotating shaft 430 are adjacent to each other. In the present embodiment, the axial direction of the first rotating shaft 420 and the axial direction of the second rotating shaft 430 are both arranged along the axial direction of the parking hub 100.

[0108] like Figure 2 As shown, in one specific embodiment,

[0109] The elastic structure 320 includes at least one elastic member 321 , wherein the at least one elastic member 321 is connected between the other end of the first friction portion 210 and the other end of the second friction portion 220 .

[0110] The electronic parking drum brake device provided by the present invention connects at least one elastic member 321 to the other end of the first friction portion 210 and the other end of the second friction portion 220, that is, connects at least one elastic member 321 between the end of the first friction portion 210 away from the first rotating shaft 420 and the end of the second friction portion 220 away from the second rotating shaft 430, so that the pulling force applied by the elastic member 321 to the first friction portion 210 relative to the torque of the first rotating shaft 420 is maximized, and the pulling force applied by the elastic member 321 to the second friction portion 220 relative to the torque of the second rotating shaft 430 is maximized, so that the first friction portion 210 and the second friction portion 220 can be quickly pulled to reset, thereby achieving the effect of quickly unlocking and parking the electronic parking drum brake device.

[0111] Specifically in this embodiment, the elastic structure 320 includes at least one elastic member 321. The elastic member 321 in this embodiment is generally a spring. In other embodiments, elastic members 321 with other structures can also be used; or in other embodiments, the elastic structure 320 can also use multiple elastic members 321, and the multiple elastic members 321 are arranged in parallel, and the two ends of each elastic member 321 are respectively connected to the first friction portion 210 and the second friction portion 220.

[0112] like Figure 3 and Figure 4 As shown, in one specific embodiment,

[0113] The pushing assembly 311 includes a pushing shaft 3111, the axis of the pushing shaft 3111 is arranged parallel to the axis of the elastic member 321, the first end 3112 and the second end 3113 are respectively connected to the two ends of the pushing shaft 3111 by threads, and the driving assembly 312 can drive the pushing shaft 3111 to rotate so that the first end 3112 and the second end 3113 can be respectively retracted or rotated out relative to the two ends of the pushing shaft 3111.

[0114] Specifically in the present embodiment, the pushing shaft 3111 is a rotatable rod, and the axis of the pushing shaft 3111 is arranged parallel to the axis of the elastic member 321, so that the pulling force of the elastic member 321 on the first friction portion 210 and the second friction portion 220 and the pushing force of the first end 3112 and the second end 3113 of the pushing shaft 3111 on the first friction portion 210 and the second friction portion 220 can be parallel, so that the pulling force and the pushing force can achieve a force balance, avoiding the imbalance of the push-pull force and causing the displacement control of the first friction portion 210 and the second friction portion 220 to be unbalanced.

[0115] like Figure 3 and Figure 4 As shown, in one specific embodiment,

[0116] The driving assembly 312 includes a driving member 3121, and the pushing assembly 311 also includes a worm wheel 3115 and a worm member 3117. The driving member 3121 has an output tooth portion 3122 that can rotate around its own axis, and the worm member 3117 has a spiral tooth portion 3118 and an input tooth portion 3119 that are spaced apart along its own axial direction. The worm wheel 3115 is sleeved on the pushing shaft 3111.

[0117] Among them, the output tooth portion 3122 is meshed and connected with the input tooth portion 3119, so that the driving member 3121 can drive the worm member 3117 to rotate around its own axis; the spiral tooth portion 3118 is meshed and connected with the worm wheel 3115, so that the worm member 3117 can drive the worm wheel 3115 to rotate and drive the driving shaft 3111 to rotate around its own axis.

[0118] The electronic parking drum brake device provided by the present invention adopts the meshing drive of the worm wheel 3115 and the worm member 3117, which simplifies the transmission structure and achieves a larger transmission ratio compared to the planetary gear drive mechanism. The meshing of the worm wheel 3115 and the worm member 3117 can also achieve the effect of transmission self-locking.

[0119] In this embodiment, the worm gear 3115 is sleeved on the driving shaft 3111, and the first end 3112 and the second end 3113 are rotated out or in relative to the two ends of the driving shaft 3111 along the axis of the driving shaft 3111 through the rotation of the driving shaft 3111 itself, so as to avoid the first end 3112 pushing the first friction part 210 to abut against the parking hub 100, and the second end 3113 pushing the second friction part 220 to abut against the parking hub 100, which is affected by the instantaneous friction force or other forces, causing the first end 3112 and the second end 3113 to retract along the axis of the driving shaft 3111, thereby affecting the parking ability of the electronic parking drum brake device during the parking process or the emergency braking ability during the emergency braking process.

[0120] In this embodiment, the driving member 3121 is a driving motor with an output shaft, and the output tooth portion 3122 is arranged at one end of the output shaft. The worm member 3117 of the pushing component 311 can rotate along its own axis, and the spiral tooth portion 3118 and the input tooth portion 3119 are sequentially arranged along the axis of the worm member 3117, wherein the driving member 3121 can drive the worm member 3117 to rotate along its own axis through the engagement of the input tooth portion 3119 with the output tooth portion 3122.

[0121] In this embodiment, the spiral tooth portion 3118 of the worm gear 3117 is meshed with the worm wheel 3115, that is, when the worm gear 3117 rotates along its own axis, it can drive the worm wheel 3115 to rotate. The worm wheel 3115 is sleeved on the driving shaft 3111, that is, the rotation of the worm wheel 3115 can drive the driving shaft 3111 to rotate along its own axis, and then rotate the first end 3112 and the second end 3113 out or in along the axis of the driving shaft 3111.

[0122] like Figure 2 and Figure 3 As shown, in one specific embodiment,

[0123] The driving member 3121 and the worm member 3117 are both extended toward the inner side of the parking hub 100 in a direction perpendicular to the axis of the driving shaft 3111 . The spiral tooth portion 3118 of the worm member 3117 is disposed close to the tail shaft, and the input tooth portion 3119 is disposed away from the tail shaft.

[0124] The electronic parking drum brake device provided by the present invention extends the driving member 3121 and the worm member 3117 toward the inner side of the parking hub 100, thereby preventing the driving member 3121 and the worm member 3117 from extending toward the outside of the parking hub 100, thereby preventing the electronic parking drum brake device from being too large to be installed on the tail shaft. At the same time, the driving member 3121 and the worm member 3117 extend in a direction perpendicular to the axis of the driving shaft 3111, thereby ensuring a stable meshing relationship and minimizing the space occupied by the driving member 3121 and the worm member 3117 inside the parking hub 100.

[0125] Related References Figure 4 As shown, in this embodiment, the axis of the driving member 3121 is parallel to the axis of the worm member 3117, the output tooth portion 3122 of the driving member 3121 is meshed and connected with the input tooth portion 3119 of the worm member 3117 along its own radial direction, the worm wheel 3115 rotates around the axis of the driving shaft 3111, and the axial direction of the worm wheel 3115 is perpendicular to the axial direction of the spiral tooth portion 3118.

[0126] like Figure 4 As shown, in one specific embodiment,

[0127] The worm wheel 3115 has a snap-in hole 3116, the axis of the snap-in hole 3116 and the axis of the worm wheel 3115 are located on the same straight line, the worm wheel 3115 is movably mounted on the driving shaft 3111 through the snap-in hole 3116, a snap-in portion 3114 is formed on the outer side of the driving shaft 3111, and the worm wheel 3115 is snap-in connected with the snap-in portion 3114 through the snap-in hole 3116, so that the worm wheel 3115 can drive the driving shaft 3111 to rotate along its own axis.

[0128] The electronic parking drum brake device provided by the present invention adopts the form of a clamping hole 3116 on the worm gear 3115 to connect with the driving shaft 3111, so that the worm gear 3115 can drive the driving shaft 3111 to rotate, and can also facilitate the worm gear 3115 to move along the axis of the driving shaft 3111, and can effectively eliminate the problem of asymmetric positions of the first end 3112 and the second end 3113 at both ends of the driving shaft 3111 caused by assembly errors, so that the first friction part 210 and the second friction part 220 can output force synchronously. At the same time, the worm gear 3115 is slidably connected to the driving shaft 3111, that is, only torque is transmitted between the worm gear 3115 and the driving shaft 3111, even if the worm gear 3115 and the driving shaft 3111 slide relative to each other, it will not affect the transmission of torque, and can ensure that the pushing force loaded on the first friction part 210 and the second friction part 220 will not act on the driving shaft 3111, the first end 3112 and the second end 3113, that is, the connection between the driving mechanism 300 and the end cover 400 is simplified, making the structure of the electronic parking drum brake device more compact.

[0129] In this embodiment, the snap-in hole 3116 is generally an opening with a square cross-section, and one section of the driving shaft 3111 forms a snap-in portion 3114 with a square cross-section. The diameter of the snap-in hole 3116 is slightly larger than the diameter of the snap-in portion 3114, so that the worm gear 3115 can move along the axis of the driving shaft 3111.

[0130] like Figure 2 As shown, in one specific embodiment,

[0131] There are two drive assemblies 312, which are respectively arranged on opposite sides of the connecting hole portion 1101. The drive members 3121 of the two drive assemblies 312 are respectively meshed and connected with opposite sides of the input tooth portion 3119 of the worm member 3117 through the output tooth portion 3122, so as to synchronously drive the worm member 3117 to rotate.

[0132] The electronic parking drum brake device provided by the present invention realizes a more compact mechanism arrangement and optimizes the volume of the electronic parking drum brake device by disposing two drive assemblies 312 on opposite sides of the connecting hole portion 1101 and arranging the worm gear 3117 between the two drive assemblies 312; furthermore, the two drive assemblies 312 can realize high braking force output while, when one drive assembly 312 fails, the other drive assembly 312 can also complete the parking brake action, effectively avoiding the problem that the wheel cannot be unlocked when a single drive assembly 312 fails, so the dual drive assembly 312 can effectively improve the reliability of the overall system.

[0133] Specifically in this embodiment, the output teeth 3122 of the driving members 3121 of the two driving assemblies 312 are respectively meshed with opposite sides of the input teeth 3119 , and the two output teeth 3122 rotate in the same direction to synchronously drive the worm member 3117 to rotate.

[0134] like Figure 4 As shown, in one specific embodiment,

[0135] The driving assembly 312 also includes a deceleration rod 3123, which is arranged between the driving member 3121 and the worm member 3117. The deceleration rod 3123 extends toward the inner side of the parking hub 100 in a direction perpendicular to the axis of the driving shaft 3111. The deceleration rod 3123 has a first deceleration tooth portion 3124 and a second deceleration tooth portion 3125 arranged at intervals along its own axial direction. The first deceleration tooth portion 3124 and the second deceleration tooth portion 3125 are respectively meshed and connected with the output tooth portion 3122 and the input tooth portion 3119, wherein the diameter of the first deceleration tooth portion 3124 is larger than the diameter of the output tooth portion 3122, so as to increase the output torque of the driving member 3121; the diameter of the second deceleration tooth portion 3125 is smaller than the diameter of the input tooth portion 3119, so as to increase the transmission torque of the deceleration rod 3123.

[0136] The electronic parking drum brake device provided by the present invention is used to increase the output torque of the driving member 3121 on the driving shaft 3111 by arranging a reduction rod member 3123 between the driving member 3121 and the worm member 3117 .

[0137] Specifically in the present embodiment, the output tooth portion 3122 of the driving member 3121 is connected by meshing with the first reduction tooth portion 3124 of the reduction rod member 3123, thereby realizing a first-stage reduction in torque. When the reduction rod member 3123 is rotating, the second reduction tooth portion 3125 of the reduction rod member 3123 is connected by meshing with the input tooth portion 3119, thereby realizing a second-stage reduction in torque. When the worm member 3117 is rotating, further reduction in torque is formed by meshing the spiral tooth portion 3118 with the worm wheel 3115.

[0138] like Figure 2 As shown, in one specific embodiment,

[0139] The parking mechanism 200 also includes a plurality of axial positioning springs 230, which are extended along the axial direction of the parking hub 100, one end of the plurality of axial positioning springs 230 is connected to the end cover 400, and the other end of the plurality of axial positioning springs 230 is respectively abutted against the first friction portion 210 or the second friction portion 220 along the axial direction of the axial positioning springs 230 toward the end cover 400, so as to pull the first friction portion 210 or the second friction portion 220 to abut against the end cover 400.

[0140] The electronic parking drum brake device provided by the present invention is provided with an axial positioning spring 230 to pull the first friction portion 210 or the second friction portion 220 to resist the end cover 400, thereby preventing the first friction portion 210 or the second friction portion 220 from being affected by external forces and causing axial displacement along the parking hub 100 during the stopping process.

[0141] Specifically in this embodiment, one end of the axial positioning spring 230 is connected to the connecting surface of the end cover 400, and a stopper 231 is formed at the other end of the axial positioning spring 230. The end surface of the stopper 231 facing the end cover 400 abuts against the first friction portion 210 or the second friction portion 220. The axial positioning spring 230 is stretched to maintain the contraction force of the axial positioning spring 230.

[0142] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An electronic parking drum brake device, characterized in that: include: A parking hub having an inner cavity, the parking hub being connected to a tail shaft of the wheel hub motor; a parking mechanism located in the inner cavity, the parking mechanism comprising a first friction portion and a second friction portion; A driving mechanism located in the inner cavity, the driving mechanism comprising a locking structure and an elastic structure, the elastic structure being connected between the first friction part and the second friction part, the locking structure comprising a pushing component and a driving component, the pushing component comprising a first end and a second end opposite to each other, the first end and the second end respectively abutting against the first friction part and the second friction part, the driving component being connected to the pushing component, and the driving component being able to drive the pushing component to rotate so as to move the first end and the second end in a direction away from or close to each other; When the first end and the second end move away from each other to a first relative position, the first end and the second end respectively push the first friction portion and the second friction portion to abut against inner walls on two opposite sides of the parking hub; When the first end and the second end move toward each other to a second relative position, the elastic structure pulls the first friction portion and the second friction portion to be separated from the inner walls on two opposite sides of the parking hub.

2. The electronic parking drum brake device according to claim 1, characterized in that: The axis of the parking hub and the axis of the tail shaft are located in the same straight line. The parking hub has a first axial end and a second axial end opposite to each other along its own axis, the first axial end is close to the tail shaft, and the second axial end is far away from the tail shaft. The first axial end is formed with a connecting hole portion extending toward the inner cavity along the rotation axis of the tail shaft, and the parking hub is connected to the tail shaft of the wheel hub motor through the connecting hole portion so that the parking hub can rotate synchronously with the tail shaft.

3. The electronic parking drum brake device according to claim 2, characterized in that: The electronic parking drum brake device further includes an end cover, which is formed at the second axial end. The end cover has a connecting wall facing the inner cavity, and the parking mechanism and the driving mechanism are respectively connected to the connecting wall.

4. The electronic parking drum brake device according to claim 3, characterized in that: The first friction part and the second friction part are both arc-shaped structures that can fit with the inner wall of the parking hub, and one end of the first friction part is disposed adjacent to one end of the second friction part and is rotatably connected to the end cover through a first rotating shaft and a second rotating shaft respectively; The other end of the first friction portion and the other end of the second friction portion can swing around the first rotation axis and the second rotation axis respectively toward a direction close to or away from the inner wall of the parking hub.

5. The electronic parking drum brake device according to claim 4, characterized in that: The elastic structure includes at least one elastic member, wherein the at least one elastic member is connected between the other end of the first friction portion and the other end of the second friction portion.

6. The electronic parking drum brake device according to claim 5, characterized in that: The pushing assembly includes a pushing shaft, the axis of the pushing shaft is arranged parallel to the axis of the elastic member, the first end and the second end are respectively connected to the two ends of the pushing shaft by threads, and the driving assembly can drive the pushing shaft to rotate so that the first end and the second end can be respectively retracted or rotated out relative to the two ends of the pushing shaft.

7. The electronic parking drum brake device according to claim 6, characterized in that: The driving assembly includes a driving member, and the pushing assembly also includes a worm wheel and a worm member, wherein the driving member has an output tooth portion that can rotate around its own axis, and the worm member has a spiral tooth portion and an input tooth portion spaced apart along its own axial direction, and the worm wheel is sleeved on the pushing shaft; Among them, the output tooth portion is meshed and connected with the input tooth portion, so that the driving member can drive the worm member to rotate around its own axis; the spiral tooth portion is meshed and connected with the worm wheel, so that the worm member can drive the worm wheel to rotate and drive the driving shaft to rotate around its own axis.

8. The electronic parking drum brake device according to claim 7, characterized in that: The driving member and the worm member are both extended toward the inner side of the parking hub in a direction perpendicular to the axis of the driving shaft, the spiral tooth portion of the worm member is arranged close to the tail shaft, and the input tooth portion is arranged away from the tail shaft.

9. The electronic parking drum brake device according to claim 7, characterized in that: The worm wheel has a clamping hole, the axis of the clamping hole and the axis of the worm wheel are located on the same straight line, the worm wheel is movably mounted on the driving shaft through the clamping hole, a clamping portion is formed on the outer side of the driving shaft, the worm wheel is clamped with the clamping portion through the clamping hole, and the worm wheel can drive the driving shaft to rotate along its own axis.

10. The electronic parking drum brake device according to claim 8, characterized in that: There are two drive assemblies, which are respectively arranged on opposite sides of the connecting hole portion. The drive members of the two drive assemblies are respectively meshed and connected with opposite sides of the input tooth portion of the worm member through the output tooth portion, so as to synchronously drive the worm member to rotate.

11. The electronic parking drum brake device according to claim 10, characterized in that: The drive assembly also includes a deceleration rod member, which is arranged between the drive member and the worm member, and extends toward the inner side of the parking hub in a direction perpendicular to the axis of the driving shaft. The deceleration rod member has a first deceleration tooth portion and a second deceleration tooth portion arranged at intervals along its own axial direction, and the first deceleration tooth portion and the second deceleration tooth portion are respectively meshed and connected with the output tooth portion and the input tooth portion, wherein the diameter of the first deceleration tooth portion is larger than the diameter of the output tooth portion, so as to increase the output torque of the drive member; the diameter of the second deceleration tooth portion is smaller than the diameter of the input tooth portion, so as to increase the transmission torque of the deceleration rod member.

12. The electronic parking drum brake device according to claim 3 or 4, characterized in that: The parking mechanism also includes a plurality of axial positioning springs, which are extended along the axial direction of the parking hub, one end of each of the axial positioning springs is connected to the end cover, and the other end of each of the axial positioning springs is respectively abutted against the first friction portion or the second friction portion in the axial direction of the axial positioning springs toward the end cover, so as to pull the first friction portion or the second friction portion to abut against the end cover.

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