A dual shaft nested transmission structure and a drive and parking redundant brake system

Abstract

The utility model discloses a kind of dual-shaft nested transmission structure and parking and parking redundancy brake system, it is related to automobile brake technical field, including the transmission structure formed by first screw rod, second screw rod, axle cylinder and push rod nesting combination, and the first brake assembly, second brake assembly and brake piston connected therewith, the first brake assembly and second brake assembly are used to provide driving torque for brake piston, the transmission structure will be converted into brake thrust control brake piston sliding;So that the utility model can be individually realized by first brake assembly and transmission structure parking brake, also can be individually realized by second brake assembly and transmission structure parking brake, or two kinds of brake force superposition output, provide safety redundancy brake guarantee, to ensure that brake system can still work normally when single motor fails.And the system is high, occupies small, higher integration degree.

Description

Technical Field

[0001] This utility model relates to the field of automotive brake technology, and in particular to a dual-shaft nested transmission structure and a redundant braking system for driving and parking. Background Technology

[0002] Electromechanical braking systems eliminate the traditional hydraulic braking force transmission method, directly driving the brakes with an electric motor to clamp the vehicle's brake discs or drums, thereby achieving braking. Its main advantages include short braking response time, high control precision, energy saving and environmental friendliness, enabling more efficient energy recovery and superior braking performance.

[0003] Electromechanical braking systems consist of two components: service brakes and parking brakes. To adapt to different application scenarios in passenger cars, commercial vehicles, or multi-purpose vehicles, electromechanical braking systems are developing towards lightweight and compact designs, redundant safety designs, and intelligent features.

[0004] CN 219115422 U discloses an electromechanical braking system and vehicle. In this system, a motor transmits power to the input end of a conversion structure via a transmission structure. The conversion structure converts the rotational motion of the input end into linear motion at its output end. The output end of the conversion structure drives a piston to move linearly, pushing brake pads against a brake disc to achieve braking. The motor drives a first gear to rotate, which in turn drives a second gear, which in turn drives a third gear. The planetary gear system includes a sun gear, planet gears, a ring gear, and a planet carrier. The ring gear is fixedly mounted on a housing. The third gear drives the sun gear via a connecting shaft, which in turn drives the planet gears, which in turn drive the planet carrier, which in turn drives a ball screw. This transmission structure can achieve a large transmission ratio within a small space. Furthermore, the ring gear is fixed to the housing via multiple connecting keys, simplifying installation and allowing for quick and easy installation. The multiple connecting keys are evenly distributed along the circumference of the ring gear, ensuring a stable and secure mounting.

[0005] The disadvantages are: 1. The parking mechanism uses an electromagnetic valve push rod to rotate the pawl so that it engages with the ratchet to limit the rotation of the motor's output shaft. The parking locking capability depends on the continuous power supply to the motor, resulting in high energy consumption and safety hazards; 2. Precise control and verification of the parking brake are required, as there is a risk that the pawl and ratchet will disengage too early, have difficulty disengaging, or become stuck; 3. The transmission system gear ring is installed to the housing via a flat key and keyway, resulting in a large system space occupation.

[0006] Patent publication number CN119554346A discloses a compact electromechanical braking mechanism integrating driving and parking functions, including a mounting bracket, a braking assembly, and a brake caliper assembly. The braking assembly includes a driving brake unit and a parking brake unit. The driving brake unit includes a brake motor and a reduction gear set. The brake caliper assembly has a brake caliper that is slidably mounted on the mounting bracket, and one end of the caliper is connected to the power end of the brake motor via the reduction gear set. The parking brake unit includes a parking motor, a ratchet, and a pawl. The ratchet is connected to the reduction gear set, and the pawl is connected to the power end of the parking motor. A buffer is provided between the pawl and the power end of the parking motor to prevent a flexible connection between the pawl and the power end of the parking motor when the ratchet fails. However, in this design, the driving motor or transmission mechanism in the driving brake fails or malfunctions, resulting in insufficient safety redundancy. Utility Model Content

[0007] This utility model provides a dual-axis nested transmission structure and a redundant braking system for driving and parking, so as to provide a braking system transmission scheme and structure with high safety redundancy, small space occupation and higher integration.

[0008] This utility model proposes a dual-axis nested transmission structure, including a first lead screw and a second lead screw, as well as a shaft cylinder and a push rod. The shaft cylinder has a through hole along its axis, and the inner wall of the through hole has a second internal thread. The second lead screw meshes with the second internal thread. The second lead screw has a sliding hole along its axis, and the push rod is placed in the sliding hole and slidably connected to the second lead screw. The push rod has a blind hole along its axis, and the inner wall of the blind hole has a first internal thread. The lower end of the first lead screw is placed in the blind hole and meshes with the first internal thread. The upper end of the first lead screw extends out of the through hole of the shaft cylinder. The upper end of the shaft cylinder and the upper end of the first lead screw are provided with a transmission connection structure.

[0009] Preferably, the push rod can slide up and down along the axis within the sliding hole of the second lead screw.

[0010] Preferably, the second lead screw is a trapezoidal lead screw, and the first lead screw is a ball screw. Alternatively, the second lead screw is a ball screw, and the first lead screw is a trapezoidal lead screw. The ball screw is used for the service brake, and the trapezoidal lead screw is used for the parking brake; the self-locking capability of the trapezoidal lead screw enables the parking brake to self-lock.

[0011] Preferably, the through hole is a stepped through hole, including a large hole section and a small hole section, the second internal thread is located on the inner wall of the large hole section, and the upper end of the first lead screw passes through the small hole section and extends out of the through hole of the shaft cylinder.

[0012] Preferably, the first lead screw is provided with a shoulder and a first thrust bearing, one side of the first thrust bearing abutting the junction of the large hole section and the small hole section, and the other side abutting the shoulder.

[0013] The transmission connection structure can be any existing structure that implements the transmission connection, such as the spline and spline groove, internal hexagonal groove and hexagonal prism structure, etc., as described in the embodiments of the specification.

[0014] This invention also proposes a redundant braking system for driving and parking, including a housing, a second braking assembly, a first braking assembly, and a brake piston. The second braking assembly, the first braking assembly, and the brake piston are all housed within the housing. The second and first braking assemblies provide driving torque to the brake piston. The system also includes the aforementioned dual-shaft nested transmission structure. The upper end of the shaft cylinder is connected to the output end of the second braking assembly, the upper end of the first lead screw is connected to the output end of the first braking assembly, and the lower ends of the second lead screw and the push rod are connected to the brake piston. The first lead screw has an anti-rotation protrusion, and the housing has a groove adapted to the anti-rotation protrusion. This invention transmits braking torque to the shaft cylinder and the first lead screw respectively through the first and second braking assemblies, and then the second lead screw and the push rod push the brake piston to compress the brake pads to complete driving braking and / or parking braking.

[0015] Preferably, the first braking assembly includes a first motor, a first transmission shaft, and a second transmission shaft. The output shaft of the first motor is equipped with a first primary braking gear, the first transmission shaft with a first secondary braking gear, and the second transmission shaft with a first tertiary braking gear. The first primary braking gear meshes with the first secondary braking gear, and the first secondary braking gear meshes with the first tertiary braking gear. The second transmission shaft is connected to a first lead screw. The braking torque is provided by the first motor and then transmitted sequentially to the first lead screw via the first primary braking gear, the first secondary braking gear, and the second transmission shaft.

[0016] Preferably, the second braking assembly includes a second motor, a third transmission shaft, and a bushing. A second primary braking gear is mounted on the output shaft of the second motor, a second secondary braking gear is mounted on the third transmission shaft, and a second tertiary braking gear is mounted on the bushing. The second primary braking gear meshes with the second secondary braking gear, and the second secondary braking gear meshes with the second tertiary braking gear. The bushing is sleeved on the second transmission shaft and rotatably connected to it. A second thrust bearing is provided between the second tertiary braking gear and the first tertiary braking gear. The bushing is connected to a shaft sleeve. The braking torque is provided by the second motor and then transmitted to the shaft sleeve sequentially via the second primary braking gear, the second secondary braking gear, and the bushing.

[0017] Preferably, the upper end of the shaft cylinder is provided with a spline, and the lower end of the bushing is provided with a corresponding spline groove, so that torque can be transmitted through the interaction of the spline and the spline groove.

[0018] Preferably, the upper end face of the second lead screw is provided with an internal hexagonal groove, and the lower end of the third transmission shaft is provided with a hexagonal prism structure adapted to the internal hexagonal groove. The torque is transmitted through the mutual cooperation of the internal hexagonal groove and the hexagonal prism structure.

[0019] Preferably, a planetary gear reduction mechanism is further provided between the second braking primary gear and the second braking secondary gear, or between the first braking primary gear and the first braking secondary gear. The second braking primary gear or the first braking primary gear is connected to the input end of the planetary gear reduction mechanism, and the output end of the planetary gear reduction mechanism is connected to the second braking secondary gear or the first braking secondary gear. This is used to further reduce and increase the torque output by the first motor and the second motor.

[0020] Preferably, the second braking secondary gear or the first braking secondary gear is a secondary reduction gear, which includes an input gear and an output gear. The number of teeth on the input gear is greater than the number of teeth on the output gear. The input gear meshes with the second braking primary gear or the first braking primary gear, and the output gear meshes with the second braking tertiary gear or the first braking tertiary gear. This is used to further reduce and increase the torque output by the first motor and the second motor.

[0021] Compared with the prior art, the beneficial effects of this utility model are: 1. This utility model achieves the integration and decoupling of braking torque by setting a first transmission component and a second transmission component. That is, it can realize the output of driving braking force independently, or the output of parking braking force independently, or the output of the two braking forces superimposed, providing a safe and redundant braking guarantee to ensure that the braking system can still work normally when a single motor fails.

[0022] 2. This utility model, through a unique structural design, arranges the second motor and the first motor in parallel, and through multi-stage gear transmission and reduction transmission mechanisms including but not limited to two-stage reduction gears and planetary gear reduction mechanisms, combined with the integrated nesting design of the first transmission component and the second transmission component, transmits the braking torque of the first motor and the second motor to the second lead screw and the first lead screw, thereby pushing the brake piston to squeeze the brake pads to achieve service braking and / or parking braking. This braking structure system is more compact, greatly reduces the space occupation, realizes the miniaturization and integration of the braking system, and takes into account the accuracy of service braking and the high torque requirements of parking braking.

[0023] 3. In parking mode, this utility model can achieve a reverse self-locking structure by using the second lead screw or the first lead screw as a trapezoidal lead screw, without the need for continuous power supply from the motor, thus improving safety and energy efficiency.

[0024] In summary, this utility model provides an integrated electromechanical braking system for driving and parking, which offers a highly efficient, safe, and responsive braking solution through its unique design, suitable for electromechanical braking systems in modern automobiles.

[0025] The detailed structure of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0026] Figure 1 This is a three-dimensional sectional view of the dual-axis nested transmission structure of Embodiment 1 of this utility model; Figure 2 This is an exploded structural diagram of the dual-axis nested transmission structure of Embodiment 1 of this utility model; Figure 3 This is an exploded cross-sectional view of the dual-axis nested transmission structure of Embodiment 1 of this utility model; Figure 4 This is a planar sectional view of one of the embodiments of the present invention, namely the dual-axis nested transmission structure. Figure 5 This is a second planar sectional view of the dual-axis nested transmission structure of Embodiment 1 of this utility model; Figure 6 This is an exploded view of the overall structure of a redundant braking system for driving and parking, according to Embodiment 2 of this utility model. Figure 7 This is a schematic diagram of the overall assembly structure of a redundant braking system for driving and parking according to Embodiment 2 of this utility model; Figure 8 This is an exploded schematic diagram of the second braking component in Embodiment 2 of this utility model; Figure 9 This is an exploded schematic diagram of the first braking component in Embodiment 2 of this utility model; Figure 10 This is a schematic diagram of the connection structure of the planetary gear reduction mechanism in Embodiment 2 of this utility model; Figure 11 This is a schematic diagram of the connection structure of the two-stage reduction gear in Embodiment 2 of this utility model.

[0027] Component names and designations: 1. Second motor; 2. Second brake primary gear; 3. Second brake secondary gear; 4. Third drive shaft; 5. First brake tertiary gear; 6. Second drive shaft; 7. First brake secondary gear; 8. First brake primary gear; 9. First drive shaft; 10. First motor; 11. Hexagonal prism structure; 12. Bushing; 13. Second brake tertiary gear; 14. Spline groove; 15. Internal hexagonal groove; 16. Anti-rotation protrusion; 17. 171. Shaft; 172. Through hole; 173. Second internal thread; 18. Spline; 19. Brake piston; 20. First lead screw; 21. Push rod; 211. Blind hole; 212. First internal thread; 22. Second lead screw; 221. Sliding hole; 23. Planetary gear reduction mechanism; 24. Second stage reduction gear; 242. Output gear; 241. Input gear; 25. First thrust bearing; 26. Radial bearing; 27. Shaft shoulder; 28. Second thrust bearing. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can be arranged and designed in various different configurations. The following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to illustrate selected embodiments of the utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0029] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. Terms such as "comprising" or "including" as used in this disclosure mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may also include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. Example 1

[0030] like Figures 1-5As shown, this utility model proposes a dual-axis nested transmission structure, including a first lead screw 20, a second lead screw 22, a shaft cylinder 17, and a push rod 21. The shaft cylinder 17 has a through hole 171 along its axis, and the inner wall of the through hole 171 has a second internal thread 172. The second lead screw 22 meshes with the second internal thread 172. The second lead screw 22 has a sliding hole 221 along its axis. The push rod 21 is placed in the sliding hole 221 and is slidably connected to the second lead screw 22. The push rod 21 has a blind hole 211 along its axis, and the inner wall of the blind hole 211 has a first internal thread 212. The lower end of the first lead screw 20 is placed in the blind hole 211 and meshes with the first internal thread 212. The upper end of the first lead screw 20 extends out of the through hole 171. The upper end of the shaft cylinder 17 and the upper end of the first lead screw 20 are provided with a transmission connection structure. This transmission structure can convert the torque input to the first lead screw 20 and the shaft cylinder 17 into the driving force of the second lead screw 22 and the push rod 21, respectively. It has high degree of freedom and high integration, and is consistent with the movement direction of the second lead screw 22 and the push rod 21. It can work together and protect each other. If one lead screw pair fails, the other lead screw pair can take over the work for a short period of time, which is of great practical value.

[0031] Preferably, the through hole 171 is a stepped through hole, including a large hole section and a small hole section, the second internal thread 172 is located on the inner wall of the large hole section, and the upper end of the first lead screw 20 extends out of the through hole 171 through the small hole section.

[0032] Preferably, the first lead screw 20 is provided with a shoulder 27 and a first thrust bearing 25. One side of the first thrust bearing 25 abuts against the junction of the large bore section and the small bore section, and the other side abuts against the shoulder 27. The first thrust bearing 25 can prevent unnecessary wear caused by sliding friction between the first lead screw 20 and the shaft cylinder 17, extend the service life of the transmission structure, and improve the working stability.

[0033] Specifically, such as Figure 4 As described above, the second lead screw 22 is a trapezoidal lead screw, and the first lead screw 20 is a ball screw. Or as... Figure 5 As shown, the second lead screw 22 is a ball screw, and the first lead screw 20 is a trapezoidal lead screw. The ball screw is used for the service brake, and the trapezoidal lead screw is used for the parking brake. The self-locking capability of the trapezoidal lead screw ensures that the braking state is maintained even if the second motor 1 and / or the first motor 10 are de-energized.

[0034] The following description uses the example of a trapezoidal lead screw 22 and a ball screw 20. Example 2

[0035] like Figure 6-11As shown, this utility model also proposes a redundant braking system for driving and parking, including a housing, a second braking assembly, a first braking assembly, and a brake piston 19. The second braking assembly, the first braking assembly, and the brake piston are all placed inside the housing. The second braking assembly and the first braking assembly are used to provide driving torque to the brake piston. It also includes the above-mentioned dual-shaft nested transmission structure. The upper end of the shaft cylinder 17 is connected to the output end of the second braking assembly through a transmission connection structure. The upper end of the first lead screw 20 is connected to the output end of the first braking assembly through a transmission connection structure. The lower ends of the second lead screw 22 and the push rod 21 are connected to the brake piston 19. The first lead screw 20 is provided with an anti-rotation protrusion 16, and the housing is provided with a sliding groove adapted to the anti-rotation protrusion 16.

[0036] In this embodiment, the braking torque is transmitted to the cylinder 17 and the first lead screw 20 by the first braking assembly and the second braking assembly respectively, and then converted into the braking thrust of the second lead screw 22 and the push rod 21. The second lead screw 22 and the push rod 21 push the brake piston 19 to squeeze the brake pads and clamp the brake disc to complete the braking. Since the movements of the first lead screw 20 and the second lead screw 22 are independent of each other, under the premise of high integration, it can realize the service braking or the parking braking separately, or the two braking methods can be superimposed. When the motor or transmission structure of one braking method fails, the other braking method can still take on part of the braking function, so that the braking system has extremely high safety redundancy.

[0037] Specifically, the first braking assembly includes a first motor 10, a first transmission shaft 9, and a second transmission shaft 6. A first primary braking gear 8 is mounted on the output shaft of the first motor 10, a first secondary braking gear 7 is mounted on the first transmission shaft 9, and a first tertiary braking gear 5 is mounted on the second transmission shaft 6. The first primary braking gear 8 meshes with the first secondary braking gear 7, and the first secondary braking gear 7 meshes with the first tertiary braking gear 5. The second transmission shaft 6 is connected to a first lead screw 20. The braking torque is provided by the first motor 10 and then transmitted sequentially to the first lead screw 20 via the first primary braking gear 8, the first secondary braking gear 7, and the second transmission shaft 6.

[0038] Specifically, the second braking assembly includes a second motor 1, a third transmission shaft 4, and a bushing 12. A second primary braking gear 2 is mounted on the output shaft of the second motor 1, a second secondary braking gear 3 is mounted on the third transmission shaft 4, and a second tertiary braking gear 13 is mounted on the bushing 12. The second primary braking gear 2 meshes with the second secondary braking gear 3, and the second secondary braking gear 3 meshes with the second tertiary braking gear 13. The bushing 12 is sleeved on the second transmission shaft 6 and rotatably connected to it. A second thrust bearing 28 is provided between the second tertiary braking gear 13 and the first tertiary braking gear 5. The bushing 12 is connected to a shaft sleeve 17. The braking torque is provided by the second motor 1 and then transmitted to the shaft sleeve 17 sequentially via the second primary braking gear 2, the second secondary braking gear 3, and the bushing 12. The second thrust bearing 28 prevents interference between the second tertiary braking gear 13 and the first tertiary braking gear 5 during rotation and also prevents mutual wear between their end faces, thus reducing their service life. It is worth noting that the first lead screw, the first drive shaft, the second drive shaft and the third drive shaft are also equipped with corresponding radial bearings 26 to achieve alignment and rotational connection with the housing, frame or other parts. Since the use of radial bearings 26 to mount shaft parts on other parts or frames is a common technique in the mechanical field, it will not be described in detail here.

[0039] Specifically, the upper end of the shaft cylinder 17 is provided with a spline 18, and the lower end of the bushing 12 is provided with a corresponding spline groove 14. The torque is transmitted through the cooperation of the spline 18 and the spline groove 14.

[0040] Specifically, the upper end face of the second lead screw 22 is provided with an internal hexagonal groove 15, and the lower end of the third transmission shaft 4 is provided with a hexagonal prism structure 11 adapted to the internal hexagonal groove 15. The torque is transmitted through the mutual cooperation of the internal hexagonal groove 15 and the hexagonal prism structure 11.

[0041] like Figure 10As shown, specifically, a planetary gear reduction mechanism 23 is also provided between the second braking primary gear 2 and the second braking secondary gear 3, or between the first braking primary gear 8 and the first braking secondary gear 7. The second braking primary gear 2 or the first braking primary gear 8 is connected to the input end of the planetary gear reduction mechanism 23, and the output end of the planetary gear reduction mechanism 23 is connected to the second braking secondary gear 3 or the first braking secondary gear 7. The internal gear ring of the planetary gear reduction mechanism 23 is assembled onto the housing using interference fitting, anti-rotation grooves and holes, or integral molding. The sun gear (i.e., the first braking primary gear 8 or the second braking primary gear 2) is assembled onto the motor output shaft using interference fitting, keyway connection, or integral molding. The planetary gear set is rotatably connected to the planet carrier, and a gear for meshing with the first braking secondary gear 7 or the second braking secondary gear 3 is located at the center of the planet carrier on the side away from the planetary gear set. The first motor 10 and the second motor 1 are further reduced in speed and increased in torque through the planetary gear reduction mechanism.

[0042] Or, such as Figure 11 As shown, alternatively, a two-stage reduction gear (24) can be directly used as the second braking two-stage gear 3 or the first braking two-stage gear 7. The two-stage reduction gear includes an input gear 241 and an output gear 242. The number of teeth of the input gear 241 is greater than the number of teeth of the output gear 242. The input gear 241 meshes with the second braking first-stage gear 2 or the first braking first-stage gear 8, and the output gear 242 meshes with the second braking third-stage gear 13 or the first braking third-stage gear 5. This is used to further reduce and increase the torque output by the first motor 10 and the second motor 1.

[0043] This embodiment is mainly to demonstrate the independent dual-axis output modes for driving and parking, therefore Figure 10 and Figure 11 The example provided is only to illustrate the structure of the output end, including but not limited to the torque output end structure design scheme for speed reduction and torque increase shown above. The planetary gear reduction mechanism 23 and the secondary reduction gear 24 can also be replaced with any kind of reduction mechanism available on the market.

[0044] This utility model discloses an electromechanical braking system integrating driving and parking brakes. Its main advantage lies in the fact that parking and driving brakes can be applied respectively by nested dual output shafts driving a trapezoidal lead screw and a ball screw, respectively. This is not limited to methods such as using a three-stage gear system, planetary gear system, or two-stage reduction gear to increase the braking torque output for both parking and driving. The driving motor and parking motor are distributed in parallel. The driving motor transmits torque to the first and second braking gears via a three-stage gear system. The first braking gear is integrally formed with or interference-fitted with the drive shaft. The first braking gear drives the drive shaft to rotate. The drive shaft has a hexagonal prism structure, which, through its engagement with an internal hexagonal groove, transmits torque to the lower ball screw. The rotating ball screw drives a push rod forward, which actuates the brake piston. The brake piston actuates the brake pads, which clamp the brake disc, thus achieving driving brake. The second motor (parking motor) transmits torque to the second braking third-stage gear via a three-gear system. The second braking third-stage gear is integrally formed with or interference-fitted with the bushing. The second braking third-stage gear drives the bushing to rotate. The bushing has a spline groove, and the bushing transmits torque to the shaft sleeve through the spline groove and spline engagement. The shaft sleeve drives the trapezoidal lead screw to rotate, and the trapezoidal lead screw pushes forward to actuate the brake piston. The brake piston actuates the brake pads, and the brake pads clamp the brake disc, thus achieving parking braking. In this utility model, the braking force of the service brake and parking brake is integrated, and the two systems share a single brake piston for power output. This design reduces the installation space of the gear system and improves the efficiency and reliability of the braking system.

[0045] Working process and principle: Service braking: The braking torque is output by the first motor 10 and transmitted sequentially through the first braking primary gear 8, the first braking secondary gear 7 and the first braking tertiary gear 5. Finally, the torque is output by the second transmission shaft 6, and then the first lead screw 20 converts the braking torque into braking thrust. Finally, the push rod pushes the brake piston 19 to squeeze the brake pads and clamp the brake disc, thus realizing the service braking function.

[0046] Parking brake: The braking torque is output by the second motor 1 and transmitted sequentially through the second braking first stage gear 2, the second braking second stage gear 3, and the second braking third stage gear 13. Finally, the torque is output by the bushing 12, and then the second lead screw 22 converts the braking torque into braking thrust. Finally, the second lead screw 22 pushes the brake piston 19 to squeeze the brake pads and clamp the brake disc, thus realizing the parking brake function. When the parking brake is completed, the second motor 1 stops working, and the parking brake is parked through the self-locking function of the parking screw.

[0047] Furthermore, when the service braking system fails, the second braking component outputs braking force through the parking trapezoidal screw, which can still achieve a certain service braking function.

[0048] Service brake + parking brake: When the vehicle requires braking force exceeding that of normal braking under certain special operating conditions, the second motor 1 outputs torque through the second braking primary gear 2, the second braking secondary gear 3, and the second braking tertiary gear 13, via the bushing 12, and then outputs braking force through the second lead screw 22. By simultaneously outputting parking brake force and service brake force, the braking force requirements under extreme braking conditions are met. When the service brake and parking brake are exhausted, both the first motor 10 and the second motor 1 stop working, and parking is achieved through the parking screw self-locking function of the parking brake system.

[0049] The above description is a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and concept of this utility model, should be covered within the protection scope of the claims of this utility model.

Claims

1. A dual-shaft nested transmission structure, comprising a first lead screw (20) and a second lead screw (22), characterized in that: It also includes a shaft cylinder (17) and a push rod (21). The shaft cylinder (17) has a through hole (171) along the axis. The inner wall of the through hole (171) has a second internal thread (172). The second lead screw (22) meshes with the second internal thread (172). The second lead screw (22) has a sliding hole (221) along the axis. The push rod (21) is placed in the sliding hole (221) and is slidably connected with the second lead screw (22). The push rod (21) has a blind hole (211) along the axis. The inner wall of the blind hole has a first internal thread. The lower end of the first lead screw (20) is placed in the blind hole (211) and meshes with the first internal thread (212). The upper end of the first lead screw (20) extends out of the through hole (171) of the shaft cylinder (17). The upper end of the shaft cylinder (17) and the upper end of the first lead screw (20) are provided with a transmission connection structure.

2. The dual-shaft nested transmission structure according to claim 1, characterized in that: The second lead screw (22) is a trapezoidal lead screw, and the first lead screw (20) is a ball screw; or the second lead screw (22) is a ball screw, and the first lead screw (20) is a trapezoidal lead screw.

3. A dual-shaft nested transmission structure according to claim 1 or 2, characterized in that: The through hole (171) is a stepped through hole, including a large hole section and a small hole section. The second internal thread (172) is located on the inner wall of the large hole section. The upper end of the first lead screw (20) passes through the small hole section and extends out of the through hole (171) of the shaft cylinder (17).

4. The dual-shaft nested transmission structure according to claim 3, characterized in that: The first lead screw (20) is provided with a shoulder (27) and a first thrust bearing (25). One side of the first thrust bearing (25) abuts against the junction of the large hole section and the small hole section, and the other side abuts against the shoulder (27).

5. A redundant braking system for driving and parking, comprising a housing, a second braking assembly, a first braking assembly, and a brake piston (19), wherein the second braking assembly, the first braking assembly, and the brake piston (19) are all housed within the housing, and the second braking assembly and the first braking assembly are used to provide driving torque to the brake piston (19), characterized in that: It also includes a dual-shaft nested transmission structure as described in any one of claims 1-4, wherein the upper end of the shaft cylinder (17) is connected to the output end of the second braking assembly, the upper end of the first lead screw (20) is connected to the output end of the first braking assembly, the lower ends of the second lead screw (22) and the push rod (21) are connected to the brake piston (19), the first lead screw (20) is provided with an anti-rotation protrusion (16), and the housing is provided with a sliding groove adapted to the anti-rotation protrusion (16).

6. A redundant braking system for driving and parking according to claim 5, characterized in that: The first braking assembly includes a first motor (10), a first transmission shaft (9), and a second transmission shaft (6). The output shaft of the first motor (10) is provided with a first braking primary gear (8), the first transmission shaft (9) is provided with a first braking secondary gear (7), and the second transmission shaft (6) is provided with a first braking tertiary gear (5). The first braking primary gear (8) meshes with the first braking secondary gear (7), the first braking secondary gear (7) meshes with the first braking tertiary gear (5), and the second transmission shaft (6) is connected to the first lead screw (20).

7. A redundant braking system for driving and parking according to claim 5, characterized in that: The second braking assembly includes a second motor (1), a third transmission shaft (4), and a bushing (12). The output shaft of the second motor (1) is provided with a second braking primary gear (2). The third transmission shaft (4) is provided with a second braking secondary gear (3). The bushing (12) is provided with a second braking tertiary gear (13). The second braking primary gear (2) meshes with the second braking secondary gear (3). The second braking secondary gear (3) meshes with the second braking tertiary gear (13). The bushing (12) is sleeved on the second transmission shaft (6) and rotatably connected to the second transmission shaft (6). A second thrust bearing (28) is provided between the second braking tertiary gear (13) and the first braking tertiary gear (5). The bushing (12) is connected to the shaft sleeve (17).

8. A redundant braking system for driving and parking according to claim 7, characterized in that: The upper end of the shaft cylinder (17) is provided with a spline (18), and the lower end of the bushing (12) is provided with a spline groove (14) adapted to the spline (18); the upper end face of the second lead screw is provided with an internal hexagonal groove (15), and the lower end of the third transmission shaft (4) is provided with a hexagonal prism structure (11) adapted to the internal hexagonal groove (15).

9. A redundant braking system for driving and parking according to claim 7, characterized in that: A planetary gear reduction mechanism (23) is also provided between the second braking primary gear (2) and the second braking secondary gear (3) or between the first braking primary gear (8) and the first braking secondary gear (7). The second braking primary gear (2) or the first braking primary gear (8) is connected to the input end of the planetary gear reduction mechanism (23), and the output end of the planetary gear reduction mechanism (23) is connected to the second braking secondary gear (3) or the first braking secondary gear (7).

10. A redundant braking system for driving and parking according to claim 7, characterized in that: The second braking secondary gear (3) or the first braking secondary gear (7) is a secondary reduction gear (24). The secondary reduction gear includes an input gear (241) and an output gear (242). The number of teeth of the input gear (241) is greater than the number of teeth of the output gear (242). The input gear (241) meshes with the second braking primary gear (2) or the first braking primary gear (8). The output gear (242) meshes with the second braking tertiary gear (13) or the first braking tertiary gear (5).

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