Parking braking system for hub driving unit and hub driving unit

Abstract

The utility model discloses a parking braking system used for a wheel hub driving unit and the wheel hub driving unit, the parking braking system comprises a motor end cover, a motor rotor shaft and a hydraulic braking structure, the hydraulic braking structure is arranged in the inner side of the motor end cover and is used for braking the motor rotor shaft; when the hydraulic braking structure is pressurized, the hydraulic braking structure relieves braking on the motor rotor shaft; and when the hydraulic braking structure relieves pressure, the hydraulic braking structure brakes the motor rotor shaft. The internal space of the motor is effectively utilized, a hydraulic braking structure and the internal space of the motor are reasonably fused together, and the braking system is compact in structure, reliable in braking, capable of saving space, capable of being matched with the speed reducer to provide large braking torque and capable of meeting the high-difficulty technology.

Description

Technical Field

[0001] The present application relates to the technical field of motors, and in particular to a parking brake system for a wheel hub drive unit and a wheel hub drive unit. Background Art

[0002] The wheel hub drive unit is a power system that highly integrates the wheel hub motor, reducer, braking system, rims and tires. It is an optimal structural product for the current distributed drive chassis.

[0003] Due to the constraints of the overall axial size, most of the current wheel hub drive units only retain the service brake system; and the structure of the traditional electronic parking brake system cannot meet the overall structural requirements of the drive unit. In addition, the parking braking torque requirement of the wheel hub drive unit is relatively large. Under the dual constraints of large braking torque and structural size, traditional parking brakes are difficult to meet the requirements.

[0004] Therefore, there is an urgent need to provide a parking brake system for a wheel hub drive unit and a wheel hub drive unit to solve the above-mentioned technical problems. Utility Model Content

[0005] The utility model provides a parking brake system for a wheel hub drive unit and a wheel hub drive unit. By effectively utilizing the internal space of a motor and reasonably integrating a hydraulic brake structure with the internal space of the motor, the utility model has a compact structure and reliable braking, which not only saves space but also can cooperate with a reducer to provide a large braking torque and meet high-difficulty technical braking system.

[0006] According to some embodiments, the utility model provides a parking brake system for a wheel hub drive unit, comprising: a motor end cover, a motor rotor shaft and a hydraulic brake structure, wherein the hydraulic brake structure is built into the inner side of the motor end cover and is used to brake the motor rotor shaft; when the hydraulic brake structure is pressurized, the hydraulic brake structure releases the brake on the motor rotor shaft; when the hydraulic brake structure is depressurized, the hydraulic brake structure brakes the motor rotor shaft.

[0007] Optionally, the motor rotor shaft includes a housing, and a rotating shaft disposed in the housing and coaxially disposed with the housing, wherein the rotating shaft is configured to drive the housing to rotate synchronously; and the hydraulic brake structure is disposed between the housing and the motor end cover.

[0008] Optionally, the hydraulic braking structure includes a piston, an inner sleeve, a spring, a static friction plate and a dynamic friction plate; one end of the inner sleeve is coaxially connected to the inner side of the motor end cover, and the other end extends into the outer shell, and the piston is coaxially sleeved on the outer side of the inner sleeve and can move axially under the action of pressurization or pressure relief; the dynamic friction plate and the static friction plate are arranged alternately and in parallel, the dynamic friction plate is installed in the outer shell of the motor rotor shaft, the static friction plate is installed on the head of the piston, and the spring is installed between the motor end cover and the tail of the piston.

[0009] Optionally, an oil chamber is formed between the piston and the inner sleeve, a first oil filling hole is provided on the outer side of the motor end cover, and a second oil filling hole is provided on the inner sleeve along its axial direction, and the second oil filling hole is respectively connected to the first oil filling hole and the oil chamber.

[0010] Optionally, a first sealing ring is provided between the end of the inner sleeve where the second oil injection hole is provided and the contact position of the motor end cover.

[0011] Optionally, second sealing rings are respectively provided on the piston at front and rear positions of the oil chamber.

[0012] Optionally, the dynamic friction plate is configured as an external spline structure, the outer shell of the motor rotor shaft is configured as an internal spline structure, and the dynamic friction plate and the outer shell cooperate with each other through splines; preferably, the dynamic friction plate is configured as a copper-based powder sintered friction plate.

[0013] Optionally, the static friction plate is configured as an internal spline structure, the inner sleeve is configured as an external spline structure, and the static friction plate and the inner sleeve cooperate with each other via splines; preferably, the static friction plate is configured as a steel friction plate.

[0014] Optionally, a pressure relief hole connected to the oil chamber is further provided on the outer side of the motor end cover, and a plug is provided in the pressure relief hole.

[0015] According to some embodiments, the utility model further provides a wheel hub drive unit, comprising the parking brake system for the wheel hub drive unit.

[0016] Beneficial effects:

[0017] The utility model cleverly utilizes the motor end cover and the internal space of the winding to install the hydraulic brake structure, utilizes the effect of the driving motor rotor shaft rotating to transmit the speed torque, and reasonably arranges the hydraulic brake structure on the motor rotor shaft, which does not affect the normal operation of the driving motor and reasonably utilizes the space structure of the entire wheel hub drive unit. The hydraulic brake structure is arranged on the entire wheel hub drive unit, which is a highly integrated built-in dry parking brake system that saves space and can cooperate with the reducer to provide large torque. The hydraulic brake structure adopts the method of depressurizing braking and pressurizing releasing braking. The specific process is that when the hydraulic brake structure is pressurized, the hydraulic brake structure releases the brake on the motor rotor shaft; when the hydraulic brake structure is depressurized, the hydraulic brake structure brakes the motor rotor shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the conventional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 is a cross-sectional schematic diagram of a parking brake system for a wheel hub drive unit in this embodiment;

[0020] Figure 2 is an exploded schematic diagram of a parking brake system for a wheel hub drive unit in this embodiment;

[0021] Figure 3 is a schematic diagram of the structure of the static friction plate in this embodiment;

[0022] Figure 4 Schematic diagram of the structure of the dynamic friction plate in this embodiment.

[0023] Figure numerals: 1. motor end cover; 11. center hole; 12. first oil filling hole; 2. motor rotor shaft; 21. housing; 22. rotating shaft; 3. hydraulic brake structure; 31. piston; 32. inner sleeve; 321. second oil filling hole; 33. spring; 34. static friction plate; 35. dynamic friction plate; 36. oil chamber; 4. fixed baffle; 5. fixing screw; 6. first sealing ring; 7. second sealing ring; 8. plug. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the embodiments of the utility model will be described in detail below in conjunction with the accompanying drawings. However, it can be understood by those skilled in the art that in each embodiment of the utility model, many technical details are proposed in order to enable readers to better understand the utility model. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed for protection of the utility model can also be implemented. The division of the following embodiments is for the convenience of description and should not constitute any limitation on the specific implementation of the utility model. The various embodiments can be combined and referenced with each other without contradiction.

[0025] The following is a detailed description of a parking brake system for a wheel hub drive unit provided by this embodiment in conjunction with the accompanying drawings. Figure 1 , Figure 2 As shown, it includes: a motor end cover 1, a motor rotor shaft 2 and a hydraulic brake structure 3, wherein the hydraulic brake structure 3 is built inside the motor end cover 1 and is used to brake the motor rotor shaft 2; when the hydraulic brake structure 3 is pressurized, the hydraulic brake structure 3 releases the brake on the motor rotor shaft 2; when the hydraulic brake structure 3 is depressurized, the hydraulic brake structure 3 brakes the motor rotor shaft 2. The inner side of the motor end cover 1 refers to the side facing the inside of the drive motor.

[0026] In this embodiment, the hydraulic brake structure 3 is installed by cleverly utilizing the motor end cover 1 and the internal space of the winding, and the hydraulic brake structure 3 is reasonably arranged on the motor rotor shaft 2 by utilizing the function of rotating the drive motor rotor shaft 2 to transmit the speed torque. This does not affect the normal operation of the drive motor and reasonably utilizes the spatial structure of the entire wheel hub drive unit. The hydraulic brake structure 3 is arranged on the entire wheel hub drive unit, which is a highly integrated built-in dry parking brake system that saves space and can cooperate with the reducer to provide a large torque. The hydraulic brake structure 3 adopts a pressure relief braking and pressure increase release braking method. The specific process is that when the hydraulic brake structure 3 is pressurized, the hydraulic brake structure 3 releases the brake on the motor rotor shaft 2; when the hydraulic brake structure 3 is depressurized, the hydraulic brake structure 3 brakes the motor rotor shaft 2.

[0027] Please continue to refer to Figure 1 , Figure 2As shown, in this embodiment, it should be noted that a center hole 11 is provided in the middle of the motor end cover 1, and the motor rotor shaft 2 is located on the inner side of the motor end cover 1 and is coaxially arranged with the center hole 11 of the motor end cover 1. The motor rotor shaft 2 can be arranged to include a circular shell 21 and a rotating shaft 22 coaxially arranged in the middle of the shell 21, and the rotating shaft 22 and the inner wall of the shell 21 can be connected through a connecting portion, so that the rotating shaft 22 and the shell 21 can rotate together. When installed, the rotating shaft 22 of the motor rotor shaft 2 extends to the position of the center hole 11 of the motor end cover 1. Among them, the hydraulic brake structure 3 is reasonably arranged between the motor end cover 1 and the shell 21.

[0028] The hydraulic brake structure 3 includes a piston 31, an inner sleeve 32, a spring 33, a static friction plate 34 and a dynamic friction plate 35. The piston 31, the inner sleeve 32, the static friction plate 34 and the dynamic friction plate 35 are all arranged as a circular ring structure. One end of the inner sleeve 32 is coaxially connected to the inner side of the motor end cover 1, and the other end extends into the outer shell 21 of the motor rotor shaft 2 and is additionally equipped with a fixed baffle 4. The inner sleeve 32 is fixedly connected to the inner side of the motor end cover 1 by adopting a fixing screw 5 or the like. The fixing screw 5 passes through the inner sleeve 32 from the outer side of the motor end cover 1 to be threadedly connected to the fixed baffle 4, thereby realizing the fixed installation between the inner sleeve 32 and the motor end cover 1.

[0029] The piston 31 is coaxially sleeved on the outer side of the inner sleeve 32 and can move axially under the action of pressure increase or pressure relief. An oil chamber 36 is configured between the piston 31 and the inner sleeve 32. A first oil injection hole 12 is opened on the outer side of the motor end cover 1. The inner sleeve 32 is opened along its axial direction at the end connected to the motor end cover 1. The second oil injection hole 321 and the first oil injection hole 12 are interconnected, and the second oil injection hole 321 is also interconnected with the oil chamber 36. Therefore, hydraulic oil can be injected into the oil chamber 36 from the oil passage composed of the first oil injection hole 12 and the second oil injection hole 321 on the outer side of the motor end cover 1. At the same time, in order to ensure the sealing of the inner sleeve 32 and the motor end cover 1 at the oil injection hole, the end face of the oil port end of the inner sleeve 32 is also sealed by using the first sealing ring 6 and the inner side of the motor end cover 1.

[0030] The dynamic friction plate 35 and the static friction plate 34 are arranged alternately and in parallel. The dynamic friction plate 35 is mounted on the housing 21 of the motor rotor shaft 2, the static friction plate 34 is mounted on the head of the piston 31, and the spring 33 is mounted between the motor end cover 1 and the tail of the piston 31. Therefore, when the hydraulic brake structure 3 is in the boost state, the hydraulic oil enters the oil chamber 36 through the oil channel formed by the first oil filling hole 12 of the motor end cover 1 and the second oil filling hole 321 of the inner sleeve 32. Under the pressure of the oil pressure, the piston 31 will be displaced to one side of the motor end cover 1 and the spring 33 will be compressed. At this time, the piston 31 drives the static friction plate 34 and the dynamic friction plate 35 to separate, and there is no speed and torque transmission; when the hub drive unit is in a stationary state, the hydraulic brake structure 3 is depressurized. Due to the lack of pressure, the spring 33 recovers its elasticity, squeezes and drives the piston 31 to move to one side of the dynamic friction plate 35, and then the piston 31 drives the static friction plate 34 and the dynamic friction plate 35 to combine. Under the action of friction force, a braking torque is generated, and the rotating shaft 22 of the drive motor rotor shaft 2 remains stationary without rotational motion. The generated torque is amplified by the reducer to output a larger torque, which meets the requirements of the parking braking torque, and the dynamic friction plate 35 and the static friction plate 34 can be engaged or separated during high-speed rotation of the motor.

[0031] In some embodiments, in order to ensure the sealing of the oil chamber 36 during the axial movement of the piston 31, a second sealing ring 7 is also provided on the piston 31. Two second sealing rings 7 are provided and are respectively located on the front and rear sides of the oil chamber 36. The use of the second sealing ring 7 can ensure the sealing of the oil chamber 36 during the axial displacement of the piston 31.

[0032] Please refer to Figure 1 , Figure 3 as well as Figure 4 As shown, in some embodiments, the dynamic friction plate 35 is configured as an external spline structure, and the interior of the housing 21 of the motor rotor shaft 2 is configured as an internal spline structure, and the dynamic friction plate 35 and the housing 21 of the motor rotor shaft 2 cooperate with each other through the spline, and then the motor rotor shaft 2 is driven to drive the dynamic friction plate 35 to rotate. Preferably, the dynamic friction plate 35 is configured as a copper-based powder sintered friction plate.

[0033] In other embodiments, the static friction plate 34 is configured as an inner spline structure, the inner sleeve 32 is configured as an outer spline structure, and the static friction plate 34 and the inner sleeve 32 cooperate with each other through the spline. Then, the static friction plate 34 can move axially on the inner sleeve 32 under the push of the piston 31. Preferably, the static friction plate 34 is configured as a steel friction plate.

[0034] Please refer to Figure 1 , Figure 2As shown, in the present embodiment, it is also necessary to explain that a pressure relief hole connected to the oil chamber 36 is provided on the outer side of the motor end cover 1, and a plug 8 is arranged in the pressure relief hole. If the hydraulic brake structure 3 fails, the plug 8 can be manually released from the outer side of the motor end cover 1 to mechanically release the brake, thereby not affecting the normal operation of the wheel hub drive unit.

[0035] In this embodiment, a wheel hub drive unit is also provided, comprising the parking brake system for the wheel hub drive unit.

[0036] Principle of the embodiment: During normal operation of the wheel hub drive unit, the parking brake system is in a pressurized state, and the hydraulic oil enters the oil chamber 36 from the oil channel formed by the first oil filling hole 12 on the outside of the motor end cover 1 and the second oil filling hole 321 of the inner sleeve 32. Under the pressure of the oil pressure, the piston 31 will be displaced to one side of the motor end cover 1 and the spring 33 will be compressed. At this time, the piston 31 drives the static friction plate 34 and the dynamic friction plate 35 to separate, and there is no speed and torque transmission; when the wheel hub drive unit is in a stationary state, the hydraulic brake structure 3 is depressurized. Due to the lack of pressure, the spring 33 recovers its elasticity, squeezes and drives the piston 31 to move to one side of the dynamic friction plate 35, and then the piston 31 drives the static friction plate 34 and the dynamic friction plate 35 to combine. Under the action of friction, a braking torque is generated, and the rotating shaft 22 of the motor rotor shaft 2 remains stationary without rotational movement.

[0037] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation on the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the scope of protection of the present invention. In addition, the claims attached to the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the attached claims or the equivalent forms of such scope and boundaries.

Claims

1. A parking brake system for a wheel hub drive unit, characterized in that: include: A motor end cover (1), a motor rotor shaft (2) and a hydraulic brake structure (3), wherein the hydraulic brake structure (3) is built into the inner side of the motor end cover (1) and is used to brake the motor rotor shaft (2); When the hydraulic brake structure (3) is pressurized, the hydraulic brake structure (3) releases the brake on the motor rotor shaft (2); When the hydraulic brake structure (3) releases pressure, the hydraulic brake structure (3) brakes the motor rotor shaft (2).

2. The parking brake system for a wheel hub drive unit according to claim 1, characterized in that: The motor rotor shaft (2) comprises a housing (21), a rotating shaft (22) disposed in the housing (21) and coaxially disposed with the housing (21), the rotating shaft (22) being configured to drive the housing (21) to rotate synchronously; the hydraulic brake structure (3) is disposed between the housing (21) and the motor end cover (1).

3. The parking brake system for a wheel hub drive unit according to claim 2, characterized in that: The hydraulic brake structure (3) comprises a piston (31), an inner sleeve (32), a spring (33), a static friction plate (34) and a dynamic friction plate (35); one end of the inner sleeve (32) is coaxially connected to the inner side of the motor end cover (1), and the other end extends into the outer shell (21); the piston (31) is coaxially sleeved on the outer side of the inner sleeve (32) and can move axially under the action of pressure increase or pressure relief; the dynamic friction plate (35) and the static friction plate (34) are arranged alternately and in parallel; the dynamic friction plate (35) is installed in the outer shell (21) of the motor rotor shaft (2); the static friction plate (34) is installed on the head of the piston (31); and the spring (33) is installed between the motor end cover (1) and the tail of the piston (31).

4. The parking brake system for a wheel hub drive unit according to claim 3, characterized in that: An oil chamber (36) is formed between the piston (31) and the inner sleeve (32); a first oil injection hole (12) is provided on the outer side of the motor end cover (1); a second oil injection hole (321) is provided on the inner sleeve (32) along its axial direction; the second oil injection hole (321) is respectively connected to the first oil injection hole (12) and the oil chamber (36).

5. The parking brake system for a wheel hub drive unit according to claim 4, characterized in that: The inner sleeve (32) is provided with a first sealing ring (6) between the end portion thereof provided with the second oil injection hole (321) and the contact position of the motor end cover (1).

6. The parking brake system for a wheel hub drive unit according to claim 4, characterized in that: Second sealing rings (7) are respectively arranged on the piston (31) at front and rear positions of the oil chamber (36).

7. The parking brake system for a wheel hub drive unit according to claim 3, characterized in that: The dynamic friction plate (35) is configured as an external spline structure, the outer shell (21) of the motor rotor shaft (2) is configured as an internal spline structure, and the dynamic friction plate (35) and the outer shell (21) cooperate with each other via splines; the dynamic friction plate (35) is configured as a copper-based powder sintered friction plate.

8. The parking brake system for a wheel hub drive unit according to claim 3, characterized in that: The static friction plate (34) is configured as an internal spline structure, the inner shaft sleeve (32) is configured as an external spline structure, and the static friction plate (34) and the inner shaft sleeve (32) cooperate with each other via splines; the static friction plate (34) is configured as a steel friction plate.

9. The parking brake system for a wheel hub drive unit according to claim 4, characterized in that: The outer side of the motor end cover (1) is also provided with a pressure relief hole connected to the oil chamber (36), and a plug (8) is arranged in the pressure relief hole.

10. A wheel hub drive unit, characterized in that: A parking brake system for a wheel hub drive unit comprising the method of any one of claims 1 to 9.

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