Wheel end electronic mechanical braking device

Abstract

The invention relates to a wheel end electronic mechanical brake device, and belongs to the technical field of automobile wheel end braking, the wheel end electronic mechanical brake device comprises a brake caliper, a speed reducing mechanism, a driving unit, an energy accumulator and a decoupler, an output shaft of the driving unit is in transmission connection with an input shaft of the speed reducing mechanism, an output shaft of the speed reducing mechanism is in transmission connection with the brake caliper, and the energy accumulator is in transmission connection with the brake caliper. The decoupler is connected with the energy storage device, the decoupler is used for driving the energy storage device to move to be combined with or separated from the driving unit, and the driving unit is used for driving an input shaft of the speed reducing mechanism to rotate, so that a friction plate of the brake caliper is driven to horizontally move to clamp or loosen an automobile brake disc. The single-wheel electronic mechanical braking device has the advantages that the problem of unexpected instability caused by motor failure of the single-wheel electronic mechanical braking device during braking in the driving process is solved through the energy storage device, the machining precision of the speed reducing mechanism can be reduced through the design of the energy storage device, and the process difficulty is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile wheel-end braking, and in particular to a wheel-end electronic mechanical braking device. Background Art

[0002] Wheel-end electronic mechanical braking systems are currently common in electric vehicles. Their structure generally consists of a motor, a reducer, and a brake caliper. The brake caliper houses a friction pad that clamps or separates from the brake disc. The pad is connected to the brake piston. The output shaft of the reducer is connected to the brake piston, and the motor is connected to the input shaft of the reducer. During normal vehicle operation, the brake pedal is pressed to apply the brake, and the brake is released when the pedal is released.

[0003] However, when in use, the existing wheel-end electronic mechanical braking system mainly relies on the operation of the motor to drive the friction plate to clamp the brake disc or retract. However, during driving, the motor may be damaged or fail during braking. Once this scenario occurs, the residual clamping force between the friction plate corresponding to the damaged motor and the brake disc will affect the stability of the vehicle's continued driving, and in severe cases, it may cause a major accident.

[0004] In addition, due to the requirements of braking performance, the design requirement for the gap between the friction plate and the brake disc cannot be too large or too small (which will affect the braking response rate). The industry also requires that electric vehicles need to have miniaturized motors and simplified transmissions (mainly reducers). This will place higher standards on the processing accuracy of the mechanical parts of the transmission part, which undoubtedly increases the process difficulty and cost.

[0005] Based on this, it is necessary to develop a wheel-end electronic mechanical braking device to solve the above technical problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a wheel-end electronic mechanical braking device, which effectively overcomes the defects of the prior art.

[0007] The technical solution of the present invention to solve the above technical problems is as follows:

[0008] A wheel-end electronic mechanical braking device includes a brake caliper, a reduction mechanism, a drive unit, an energy accumulator and a decoupler. The output shaft of the drive unit is transmission-connected to the input shaft of the reduction mechanism, the output shaft of the reduction mechanism is transmission-connected to the brake caliper, the decoupler is connected to the energy accumulator, the decoupler is used to drive the energy accumulator to move to engage with or disengage from the drive unit, and the drive unit is used to drive the input shaft of the reduction mechanism to rotate, thereby driving the friction plate of the brake caliper to translate to clamp or release the vehicle brake disc.

[0009] On the basis of the above technical solution, the present invention can also be improved as follows.

[0010] Furthermore, the energy accumulator includes a coil spring, a fixing device and a core shaft, the outer end of the coil spring is connected and fixed to the fixing device, the core shaft coaxially passes through the center of the coil spring and is connected and fixed to the inner end of the coil spring, the core shaft is coaxially arranged with the output shaft of the drive unit, and the decoupler is movably connected to the core shaft for driving the core shaft to move to engage with or separate from the output shaft end of the drive unit.

[0011] Furthermore, a groove is coaxially provided at one end of the core shaft, and the output shaft of the drive unit extends into the groove. The decoupler is used to drive the core shaft to move axially until the output shaft of the drive unit abuts against or separates from the groove. The bottom surface of the groove and the end of the output shaft of the drive unit are both rough surfaces.

[0012] Furthermore, the decoupler is rotatably connected to the corresponding end portion of the core shaft via a plane bearing.

[0013] Furthermore, the above-mentioned decoupler is a solenoid valve push rod.

[0014] Furthermore, a locking structure is provided at one end of the core shaft away from the output shaft of the driving unit, and the locking structure is used to lock the core shaft with the core shaft after the core shaft is separated from the output shaft of the driving unit.

[0015] Furthermore, the locking structure is a locking pin vertically arranged at the end of the core shaft, and an end of the core shaft away from the output shaft of the driving unit is provided with a socket for plugging with the locking pin.

[0016] Furthermore, the above-mentioned jack is an arc hole coaxially arranged with the above-mentioned core shaft.

[0017] Furthermore, the driving unit is a motor.

[0018] Furthermore, the decoupler and the drive unit are respectively connected to a control system, which is used to monitor the current changes of the drive unit and determine the energy storage status of the energy storage device based on the current changes of the drive unit. After the energy storage device is fully charged, the control system controls the operation of the decoupler and drives the energy storage device to move and separate from the drive unit. When the power supply of the drive unit fails, the control system controls the operation of the decoupler and drives the energy storage device to move and combine with the drive unit.

[0019] The beneficial effects of the present invention are: reasonable structural design, and the energy accumulator solves the problem of unexpected instability caused by failure of the motor of a single-wheel electronic mechanical brake device during braking during driving, thereby improving the safety performance of the vehicle. In addition, the design of the energy accumulator can reduce the processing accuracy of the deceleration mechanism and reduce the process difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A simplified diagram of the structure distribution of the wheel-end electronic mechanical brake device involved in the wheel-end electronic mechanical brake device of the present invention;

[0021] Figure 2 Schematic diagram of the structure of the energy storage device in the wheel-end electronic mechanical brake device of the present invention;

[0022] Figure 3 It is a structural schematic diagram of the cooperation between the energy storage device and the drive unit in the wheel-end electronic mechanical brake device of the present invention;

[0023] Figure 4 It is a structural schematic diagram of the combination of the energy storage device and the drive shaft of the drive unit in the wheel-end electronic mechanical brake device of the present invention;

[0024] Figure 5 It is a schematic structural diagram of the separation of the energy storage device and the drive shaft of the drive unit in the wheel-end electronic mechanical brake device of the present invention;

[0025] Figure 6 This is a control logic block diagram of the operation of the wheel-end electronic mechanical brake device of the present invention.

[0026] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0027] 1. Drive unit; 2. Energy accumulator; 3. Decoupler; 21. Coil spring; 22. Fixing device; 23. Mandrel; 24. Locking structure. DETAILED DESCRIPTION

[0028] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0029] Example

[0030] like Figures 1 to 5As shown, the wheel-end electronic mechanical brake device of this embodiment includes a brake caliper (indicated by A in the figure), a reduction mechanism (indicated by B in the figure), a drive unit 1, an energy accumulator 2 and a decoupler 3. The output shaft of the drive unit 1 is drivingly connected to the input shaft of the reduction mechanism (the input shaft of the reduction mechanism is connected to the output shaft of the drive unit 1 through a transmission structure of a chain and a sprocket, which belongs to a conventional transmission structure design and is not described here). The output shaft of the reduction mechanism is drivingly connected to the brake caliper. The decoupler 3 is connected to the energy accumulator 2 and is used to drive the energy accumulator 2 to move to engage with or separate from the drive unit 1. When the drive unit 1 is engaged with the energy accumulator 2, the drive unit 1 is used to drive the input shaft of the reduction mechanism to rotate, thereby driving the friction pad of the brake caliper to translate to clamp the vehicle brake disc and simultaneously driving the energy accumulator 2 coupled thereto to store energy. The energy accumulator 2 is used to drive the drive unit 1 to rotate when the power supply of the drive unit 1 fails, thereby driving the friction pad of the brake caliper to translate to separate from the vehicle brake disc.

[0031] The operating principle of the wheel-end electronic mechanical brake device of this embodiment is as follows:

[0032] Under normal operating conditions, the output shaft of the energy accumulator 2 and the drive unit 1 remain disconnected (separated). During driving, after the brake pedal is depressed, the drive unit 1 drives the input shaft of the deceleration mechanism to rotate, thereby driving the friction pads of the brake caliper to translate and clamp the vehicle's brake disc. At the same time, the energy accumulator 2 is coupled to the output shaft of the drive unit 1, and the drive unit 1 drives the coupled energy accumulator 2 to operate and store energy. When the drive unit 1 is damaged or fails, or the power supply to the drive unit 1 fails, the decoupler 3 is triggered, driving the energy accumulator 2 to couple with the drive shaft of the drive unit 1. Driven by the mechanical energy stored in the energy accumulator 2, the drive unit 1 rotates in the reverse direction, thereby causing the friction pads to quickly retreat (the output shaft of the drive unit 1 is driven by the energy accumulator 2 to rotate in the reverse direction, thereby driving the deceleration mechanism to reverse and the friction pads to retreat), reducing the residual clamping force between the brake pads and the brake disc, ensuring that the vehicle does not lose stability.

[0033] As a preferred embodiment, the energy accumulator 2 includes a coil spring 21, a fixing device 22 and a core shaft 23. The outer end of the coil spring 21 is connected and fixed to the fixing device 22. The core shaft 23 coaxially passes through the center of the coil spring 21 and is connected and fixed to the inner end of the coil spring 21. The core shaft 23 is coaxially arranged with the output shaft of the drive unit 1. The decoupler 3 is movably connected to the core shaft 23 for driving the core shaft 23 to move to engage with or separate from the output shaft end of the drive unit 1.

[0034] In the above embodiment, the fixing device 22 is mainly connected and fixed to the exposed end of the coil spring 21. When storing energy, the core shaft 23 is coupled with the output shaft of the drive unit 1, and the drive unit 1 drives the core shaft 23 to rotate, thereby causing the coil spring 21 to roll inward and contract to achieve energy storage. When the energy storage is full, the torque of the core shaft 23 will fluctuate, that is, the torque of the output shaft of the drive unit 1 will fluctuate, thereby accurately judging whether the energy storage of the coil spring 21 is full. When the drive unit 1 fails or the power supply fails, the core shaft 23 is driven by the decoupler 3 to move to couple with the output shaft of the drive unit 1, and the coil spring 21 releases "energy" and drives the output shaft of the drive unit 1 to rotate in the opposite direction, thereby achieving the retraction of the friction plate and reducing the residual clamping force between the friction plate and the brake disc. The overall structural design is very reasonable and ingenious.

[0035] In this embodiment, one end of the core shaft 23 is coaxially provided with a groove, and the output shaft of the drive unit 1 extends into the groove. The decoupler 3 is used to drive the core shaft 23 to move axially until the output shaft of the drive unit 1 abuts against or separates from the groove. The bottom surface of the groove and the end of the output shaft of the drive unit 1 are both rough surfaces. The output shaft of the drive unit 1 ( Figure 4 The friction contact between the core shaft 23 and the core shaft 23 is adopted to realize the combination of the two, which is simpler in design, easy to implement, and more stable in transmission. At the same time, the rough surface design makes the combination of the two closer and the transmission more stable.

[0036] In this embodiment, the above-mentioned decoupler 3 is rotationally connected to the corresponding end portion of the above-mentioned core shaft 23 through a plane bearing (represented by 3a in the figure), ensuring that the decoupler 3 can drive the core shaft 23 to move axially while the core shaft 23 can also meet the performance of good rotation relative to it, thereby realizing effective energy storage of the energy accumulator 2.

[0037] In this embodiment, the above-mentioned decoupler 3 adopts an electromagnetic valve push rod. The default state of the electromagnetic valve is that the electromagnetic valve is energized after the controller connected to it is powered on, the push rod is in an extended state, and the core shaft 23 is offset from the output shaft end of the drive unit 1. If the energy storage device 2 is full of energy, the decoupler 3 will be disconnected, and the decoupler 3 will drive the core shaft 23 to retract and separate from the output shaft end of the drive unit 1.

[0038] Of course, the decoupler 3 may also be a cylinder or an electric push rod with good adaptability.

[0039] As a preferred embodiment, a locking structure 24 is provided at one end of the core shaft 23 away from the output shaft of the drive unit 1 , and the locking structure 24 is used to lock with the core shaft 23 after the core shaft 23 is separated from the output shaft of the drive unit 1 .

[0040] In the above embodiment, when the coil spring 21 is fully stored when it is rolled inward, the decoupler 3 drives the core shaft 23 to retract rapidly, so that the core shaft 23 and the locking structure 24 are quickly locked, thereby suppressing the "unwinding" of the coil spring 21 to release mechanical energy, ensuring that the coil spring 21 is well preserved for standby use after the energy storage is full.

[0041] As a preferred embodiment, the locking structure 24 is a locking pin vertically arranged at the axial end of the core shaft 23, and the end of the core shaft 23 away from the output shaft of the driving unit 1 is provided with a socket for plugging with the locking pin.

[0042] In the above embodiment, the locking structure 24 is simply designed and is plugged into the socket at the end of the core shaft 23. After the coil spring 21 completes energy storage, the core shaft 23 quickly retracts to allow the locking pin to be inserted into the socket, preventing the core shaft 23 and the coil spring 21 from "unwinding" and rotating, thereby avoiding failure of mechanical energy storage.

[0043] It should be supplemented that the fixing device 22 of the energy accumulator 2 and the drive unit 1 are both installed in a housing, the fixing device 22 is connected and fixed to the inner wall of the housing, and the locking structure 24 is fixed in the housing.

[0044] In this embodiment, the insertion hole is a circular arc hole coaxially arranged with the core shaft 23. Since the core shaft 23 is driven back by the decoupler 3 and separated from the output shaft of the drive unit 1 during the short period of time, and the position of the core shaft 23 is basically fixed when the energy accumulator 2 is fully charged, even if the coil spring 21 slightly "unwinds" during the retraction, the circular arc hole design of the insertion hole allows the locking pin to be inserted into the insertion hole even with the core shaft 23's slight rotation, thereby suppressing the loss of energy stored in the energy accumulator 2. This is a very clever design.

[0045] In this embodiment, the driving unit 1 adopts a motor of an adapted model.

[0046] In this embodiment, Figure 6 As shown ( Figure 6 (Y indicates yes, N indicates no), the decoupler 3 and drive unit 1 are respectively connected to a control system, which is used to monitor the current changes of the drive unit 1 and determine the energy storage status of the energy accumulator 2 based on the current changes of the drive unit 1. After the energy accumulator 2 is fully charged, the control system controls the operation of the decoupler 3 and drives the energy accumulator 2 to move and separate from the drive unit 1. When the power supply of the drive unit 1 fails, the control system controls the operation of the decoupler 3 and drives the energy accumulator 2 to move and combine with the drive unit 1. The control system adopts an adapted model of ECU (on-board computer). Figure 6The block diagram describes the operating sequence of the energy accumulator 2. After the wheel-end electronic mechanical brake device is powered on, it detects whether the energy accumulator 2 has stored energy. The judgment logic is to detect the torque inflection point of the motor (that is, the drive unit 1). Because of the design, there is an idle travel before the brake friction pad contacts the brake disc. This idle travel is used to charge the energy accumulator. When the energy accumulator 2 is fully charged, the torque feedback value will rise sharply. In this case, the motor will experience a torque inflection point. When the torque inflection point occurs, the motor current also increases sharply. When the ECU recognizes the motor torque inflection point, it will control the decoupler 3 to operate, causing the core shaft 23 to separate from the output shaft of the drive unit 1, allowing the drive unit 1 to operate normally. When the conditions {vehicle in motion &&EMB has unexpected clamping &&driver has no braking request &&motor-related fault} are met, the ECU will drive the decoupler 3 to operate, causing the core shaft 23 to abut against the end of the output shaft of the drive unit 1. Eventually, the friction plate will return to the zero position, ensuring that there is no residual clamping force between the friction plate and the brake disc. If the energy accumulator 2 is detected to have no energy stored after power is turned on, the ECU will wait for the driver to step on the brake pedal, and then start storing energy after the motor is running.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0049] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0050] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0051] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0052] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A wheel-end electronic mechanical brake device, characterized in that: The invention comprises a brake caliper, a deceleration mechanism, a drive unit (1), an energy accumulator (2) and a decoupler (3), wherein the output shaft of the drive unit (1) is in transmission connection with the input shaft of the deceleration mechanism, the output shaft of the deceleration mechanism is in transmission connection with the brake caliper, the decoupler (3) is connected with the energy accumulator (2), the decoupler (3) is used to drive the energy accumulator (2) to move to be combined with or separated from the drive unit (1), and the drive unit (1) is used to drive the input shaft of the deceleration mechanism to rotate, thereby driving the friction plate of the brake caliper to translate to clamp or release the automobile brake disc.

2. A wheel-end electronic mechanical brake device according to claim 1, characterized in that: The energy accumulator (2) comprises a coil spring (21), a fixing device (22) and a core shaft (23); the outer end of the coil spring (21) is fixedly connected to the fixing device (22); the core shaft (23) coaxially passes through the center of the coil spring (21) and is fixedly connected to the inner end of the coil spring (21); the core shaft (23) is coaxially arranged with the output shaft of the drive unit (1); the decoupler (3) is movably connected to the core shaft (23) and is used to drive the core shaft (23) to move to engage with or separate from the output shaft end of the drive unit (1).

3. A wheel-end electronic mechanical brake device according to claim 2, characterized in that: A groove is coaxially provided at one end of the core shaft (23), and the output shaft of the drive unit (1) extends into the groove. The decoupler (3) is used to drive the core shaft (23) to move axially until the output shaft of the drive unit (1) abuts against or separates from the groove. The bottom surface of the groove and the end of the output shaft of the drive unit (1) are both rough surfaces.

4. A wheel-end electronic mechanical brake device according to claim 3, characterized in that: The decoupler (3) is rotatably connected to the corresponding end portion of the core shaft (23) via a plane bearing.

5. The wheel-end electronic mechanical brake device according to claim 3, characterized in that: The decoupler (3) is a solenoid valve push rod.

6. A wheel-end electronic mechanical brake device according to claim 5, characterized in that: A locking structure (24) is provided at one end of the core shaft (23) away from the output shaft of the drive unit (1), and the locking structure (24) is used to lock with the core shaft (23) after the core shaft (23) is separated from the output shaft of the drive unit (1).

7. The wheel-end electronic mechanical brake device according to claim 6, characterized in that: The locking structure (24) is a locking pin arranged perpendicularly to the axial end of the core shaft (23); an end of the core shaft (23) away from the output shaft of the drive unit (1) is provided with a socket for plugging with the locking pin.

8. The wheel-end electronic mechanical brake device according to claim 7, characterized in that: The insertion hole is a circular arc hole coaxially arranged with the core shaft (23).

9. The wheel-end electronic mechanical brake device according to claim 6, characterized in that: The driving unit (1) is a motor.

10. The wheel-end electronic mechanical brake device according to claim 9, characterized in that: The decoupler (3) and the drive unit (1) are respectively connected to a control system, the control system being used to monitor the current change of the drive unit (1) and to judge the energy storage state of the energy storage device (2) according to the current change of the drive unit (1). After the energy storage device (2) is fully stored, the control system controls the decoupler (3) to operate and drives the energy storage device (2) to move and separate from the drive unit (1). When the power supply of the drive unit (1) fails, the control system controls the decoupler (3) to operate and drives the energy storage device (2) to move and combine with the drive unit (1).

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