An electromechanical parking mechanism, its design method, and its control method

Abstract

This invention discloses an electromechanical parking mechanism, its design method, and its control method. The electromechanical parking mechanism includes a stationary disc mounted on the spindle of an EMB drive motor and a double-sided locking mechanism. The stationary disc is fixedly connected to the spindle of the EMB drive motor. The double-sided locking mechanism includes a moving disc and a linear drive mechanism. The linear drive mechanism includes a helical gear and a rotary drive mechanism. The helical gear and the moving disc are located on opposite sides of the stationary disc. The moving disc is slidably connected to a housing. The helical gear and the moving disc are connected via a threaded transmission structure. The rotary drive mechanism includes a brushed motor and a worm gear. The worm gear is mounted on the spindle of the brushed motor, and the worm gear meshes with the helical gear to form a vertically staggered arrangement. The electromechanical parking mechanism of this invention uses a double-sided locking method, which provides a higher safety factor and a lower risk of vehicle brake failure or lock-up during driving.

Description

Technical Field

[0001] This invention belongs to the field of vehicle braking control technology, specifically relating to an electromechanical parking mechanism, its design method, and its control method. Background Technology

[0002] A drive-by-wire chassis is essential for the successful implementation of advanced autonomous driving technology. The electromechanical braking system (EMB) completely eliminates hydraulic / pneumatic devices, making it a truly pure drive-by-wire braking system. This achieves decoupling between the driver and vehicle, facilitates the integration of parking functions, and enhances vehicle active safety and handling stability, making it an ideal braking actuator for advanced autonomous driving technology. The EMB uses an electric motor as the driving force output for the brake, which is then reduced and amplified by a reducer assembly to output the required braking force. Next, a motion conversion mechanism converts the rotational motion into linear translational motion, which in turn drives the brake pads of the caliper to lock the brake disc, achieving braking. Among these mechanisms, ball screws are considered an effective solution for the motion conversion mechanism of the EMB due to their high transmission efficiency, long lifespan, and high transmission precision.

[0003] It is worth noting that ball screw pairs lack self-locking functionality and cannot maintain braking force when deployed on an EMB. Therefore, to enable the EMB to perform both parking and temporary parking functions, a parking mechanism needs to be deployed on the EMB assembly. Specifically, the parking mechanism assists the EMB in providing sufficient parking force to the vehicle without dissipation. Currently, although researchers have proposed many EMB parking mechanisms, existing technical solutions are not yet mature and many problems remain to be solved. Structurally, the principles of existing publicly available EMB parking mechanisms are mainly divided into ratchet and pawl combined with solenoid valve type and wedge-plate friction disc combined with solenoid valve type. For example, utility model patents with authorization announcement numbers CN221800560U and CN221610450U both demonstrate friction disc type EMB parking mechanisms; while invention patent application with application publication number CN 117905879 A and utility model patent with authorization announcement number CN219115422 U disclose ratchet and pawl type EMB parking mechanisms. It is worth noting that ratchet-pawl parking mechanisms have the problem of difficulty in controlling the pawl to accurately land in the target ratchet groove when parking, thus failing to achieve precise locking. This results in high control difficulty, insufficient parking braking force, and a high risk of vehicle rollover. Furthermore, there is currently no effective control method to accurately land the pawl in the target ratchet groove. In addition, ratchet-pawl parking mechanisms generally use an elastic element to hold the pawl when not parked. During driving, harsh vibration environments can easily cause the elastic element to break and fail, leading to the pawl getting stuck in the ratchet teeth, which can result in vehicle lock-up or EMB service brake failure, as disclosed in the invention patent application CN117905879 A, ​​"Electromechanical Parking Self-Locking Mechanism, Control Method, and Vehicle". Existing wedge friction disc combined with solenoid valve actuators are large in size and difficult to deploy on EMB assemblies, especially for passenger vehicles with limited space. Moreover, friction disc parking mechanisms usually use knurled patterns to achieve friction braking, but the knurled patterns are prone to wear and failure after a period of use, posing a high risk. Meanwhile, most existing parking mechanisms use solenoid valves as the power source for the parking mechanism. The solenoid valves need to be kept energized when the vehicle is in motion (i.e., not parked), which makes solving the energy consumption of the whole vehicle another major problem. It does not meet the design requirements in terms of safety and energy consumption, and therefore it is difficult to apply it in actual industrial applications. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides an electromechanical parking mechanism. The electromechanical parking mechanism adopts a double-sided locking method, which has a higher safety factor, lower energy consumption, is more convenient to deploy on EMB actuators, and has a lower risk of vehicle brake failure or lock-up during driving.

[0005] The second objective of this invention is to provide a design method for an electromechanical parking mechanism.

[0006] The third objective of this invention is to provide a control method for an electromechanical parking mechanism.

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

[0008] An electromechanical parking mechanism includes a stationary disc mounted on the spindle of an EMB drive motor and a double-sided locking mechanism for locking the stationary disc, wherein...

[0009] The static disk is fixedly connected to the main shaft of the EMB drive motor;

[0010] The double-sided locking mechanism includes a movable disk and a linear drive mechanism for driving the movable disk to perform linear motion. The linear drive mechanism includes a helical gear and a rotary drive mechanism for driving the helical gear to rotate. The helical gear and the movable disk are located on opposite sides of the stationary disk and are coaxially arranged. The movable disk is mounted on the housing via a sliding connection structure. The sliding connection structure enables the movable disk to move along the axial direction of the main shaft of the EMB drive motor. The helical gear and the movable disk are connected via a threaded transmission structure.

[0011] A friction structure is provided between the helical gear and the stationary disk, and a ratchet structure is provided between the moving disk and the stationary disk;

[0012] The rotary drive mechanism includes a brushed motor and a worm gear, wherein the worm gear is mounted on the spindle of the brushed motor, and the worm gear and the helical gear are arranged in a perpendicular and staggered meshing manner.

[0013] Furthermore, the stationary disc is provided with a first locking surface and a second locking surface on both sides, wherein the helical gear is provided with a third locking surface at a position corresponding to the first locking surface; the friction structure includes knurled patterns respectively provided on the first locking surface and the third locking surface; the moving disc is provided with a fourth locking surface at a position corresponding to the second locking surface, and the ratchet structure includes ratchet teeth respectively provided on the second locking surface and the fourth locking surface.

[0014] Furthermore, a spline is provided between the stationary disk and the spindle of the EMB drive motor, and the spline is fixedly mounted on the spindle of the EMB drive motor; the stationary disk is fixedly mounted on the spline.

[0015] Furthermore, the sliding connection structure includes multiple sets of anti-rotation limiting pins disposed on the moving disk, the multiple sets of anti-rotation limiting pins being evenly arranged along the circumferential direction of the moving disk; the outer shell is provided with multiple sets of limiting holes that cooperate with the anti-rotation limiting pins.

[0016] Furthermore, the threaded transmission structure includes an internal thread disposed in the inner cavity of the helical gear, the outer diameter of the internal thread being larger than the outer diameter of the stationary disc; an external thread that mates with the internal thread is disposed on the outer circumferential surface of the moving disc; in the initial state, the external thread and the internal thread are in a mating state.

[0017] A design method for an electromechanical parking mechanism includes the following steps:

[0018] Step S1: Calculate the clamping force required for parking and the parking brake torque required by the spindle of the EMB drive motor based on the vehicle information.

[0019] Step S2: Based on the parking brake torque required by the spindle of the EMB drive motor, optimize the ratchet parameters of the ratchet structure between the second locking surface of the stationary disc and the fourth locking surface of the moving disc.

[0020] Step S3: Design the parameters of the anti-rotation limit pin on the moving plate according to the parking brake torque required by the spindle of the EMB drive motor.

[0021] Furthermore, in step S1, the calculation process for the parking brake torque required by the spindle of the EMB drive motor is as follows:

[0022] Step S101: Calculate the parking braking torque N required for a single wheel of the vehicle based on the vehicle information;

[0023] Step S102: Calculate the braking force F required for parking a single wheel of the vehicle by using the parking braking torque N required for a single wheel and the wheel braking radius b. b :

[0024]

[0025] In the formula, σ is the parking braking force safety factor, σ>1, and the value range is [1.2, 1.5];

[0026] Step S103: Measure the required braking force F of the vehicle. b The friction coefficient μ1 between the brake disc and the piston is used to calculate the piston thrust F required by the EMB actuator when parking.

[0027]

[0028] Step S104: Calculate the torque N required to achieve the target parking thrust at the screw end using the piston thrust F of the EMB during parking and the lead screw lead L1. s ;

[0029]

[0030] In the formula: η1 represents the efficiency of the ball screw assembly, and η2 represents the efficiency of the EMB clamp assembly;

[0031] Step S105: Maintain the torque N required at the lead screw input end when holding the parking thrust. s And the transmission ratio i1 of the EMB reducer assembly; calculate the torque N required by the spindle of the EMB drive motor. a ;

[0032]

[0033] Furthermore, in step S2, the design steps for the ratchet parameters of the ratchet structure in the second locking surface of the stationary disk and the fourth locking surface of the moving disk are as follows:

[0034] Step S201: Calculate the frictional torque N required between the first locking surface of the stationary disc and the third locking surface of the helical gear. h ;

[0035]

[0036] Where: N d ξ1 is the rated torque of the brushed motor; μ2 is the coefficient of friction between the first locking surface of the stationary disc and the third locking surface of the helical gear; i2 is the transmission ratio between the interlaced helical gears; ξ1 is the transmission efficiency between the interlaced helical gears; r a η3 is the thread radius of the threaded transmission structure between the helical gear and the moving disk; η3 is the transmission efficiency of the threaded transmission structure between the helical gear and the moving disk.

[0037] Step S202: Determine the torque N required by the spindle of the EMB drive motor. a and the frictional torque N between the first locking surface of the stationary disc and the third locking surface of the helical gear. h Calculate the parking torque N required between the second locking surface of the stationary disc and the fourth locking surface of the moving disc. j ;

[0038] N j =N a -N h ;

[0039] Step S203: Based on the parking torque N jAnd the centripetal angle θ corresponding to a single ratchet, calculate the number of ratchet teeth C, and then calculate the torque N that each ratchet needs to bear. c ;

[0040]

[0041]

[0042] Step S204: Based on the torque N required for each ratchet... c The radius R of the stationary disc and the radius r of the center hole of the stationary disc are calculated, where the radius r of the center hole of the stationary disc is determined by the spindle of the EMB drive motor; the shear force F borne by each ratchet tooth is calculated. c ;

[0043]

[0044] Step S205: Calculate the radial cross-sectional area S of each ratchet tooth using the radius R of the stationary disk, the radius r of the center hole of the stationary disk, and the number of ratchet teeth C.

[0045]

[0046] Step S206: Determine the radial cross-sectional area S of each ratchet tooth, and determine the shear force F borne by each ratchet tooth. c Calculate the shear strength τ1 borne by each ratchet tooth;

[0047]

[0048] Step S207: Apply a safety constraint to the shear strength τ1 borne by each ratchet, i.e.:

[0049]

[0050] In the formula: τ allow This represents the allowable shear strength of the materials for the moving and stationary disks, where K represents the safety factor, and K < 1.

[0051] Step S208: Construct the minimum static disk radius calculation model:

[0052]

[0053] Under the premise of satisfying safety constraints, the calculation model for the minimum static disk radius is solved to obtain the minimum static disk radius R.

[0054] Preferably, in step S3, the step of designing the parameters of the anti-rotation limit pin on the moving disk is as follows:

[0055] Step S301: The torque N required for the spindle of the motor driven by the EMB is determined. aGiven the number of anti-rotation limit pins k, calculate the torque N required for each anti-rotation limit pin on the drive disc. k ;

[0056]

[0057] Step S302: The torque N required to be provided by each anti-rotation limit pin on the moving plate. k Calculate the shear force F acting on each anti-rotation limit pin on the moving plate by taking the distance D from the center of the axis of each anti-rotation limit pin to the center of the axis of the moving plate. k ;

[0058]

[0059] Step S303: Based on the shear force F exerted on each anti-rotation limit pin on the moving disc... k Given the cross-sectional area A of the anti-rotation limiting pin, calculate the shear strength τ of the anti-rotation limiting pin. k ;

[0060]

[0061] In the formula: d represents the diameter of the anti-rotation limit pin;

[0062] Step S304: The shear strength τ of each anti-rotation limit pin k Apply safety constraints, namely:

[0063] τ k ≤Kτ allow ;

[0064] In the formula: τ allow K represents the allowable shear strength of the material of the anti-rotation limit pin, K represents the safety factor, and K < 1;

[0065] Step S305: Construct the minimum diameter model of the anti-rotation limit pin;

[0066]

[0067] Under the premise of meeting safety constraints, the minimum diameter model of the anti-rotation limit pin is solved to calculate the minimum diameter d of the anti-rotation limit pin.

[0068] A control method for an electromechanical parking mechanism includes the following steps:

[0069] Step 1: When the EMB is used for parking, the EMB drive motor drives the spindle to build up an initial parking pressure F2 that is greater than the actual required parking pressure F1.

[0070] F2 = x1F1;

[0071] In the formula: x1 represents the multiple of the initial parking force required by the EMB drive motor compared to the theoretically calculated parking force; F1 represents the theoretically calculated parking force, which is selected based on the specific vehicle model; x1 > 1, and its value ranges from 1.2 to 1.5.

[0072] Step 2: The brushed motor drives the worm gear to rotate, which in turn drives the helical gear to rotate. At the same time, the rotation of the helical gear drives the moving plate to move axially through the threaded transmission structure, thereby clamping the stationary plate between the helical gear and the moving plate.

[0073] Step 3: The rotation angle of the brushed motor is detected by an angle sensor installed on the brushed motor, and the axial movement stroke of the moving plate is calculated to determine whether the ratchet on the stationary plate and the ratchet on the moving plate are fully engaged.

[0074] Specifically, the required rotation angle θ of the helical gear is calculated based on the travel of the moving disc when the ratchet pairs of the second and fourth locking surfaces are fully engaged. hg :

[0075]

[0076] In the formula: x2 represents the axial movement distance of the moving plate when stable parking is achieved, i.e., when the ratchet on the stationary plate is fully engaged with the ratchet on the moving plate; L2 represents the pitch of the threaded transmission structure between the helical gear and the moving plate; θ hg Indicates the target rotation angle of the helical gear;

[0077] Next, based on the transmission ratio of the interleaved helical gears, the target rotation angle θ required for the brushed motor shaft to rotate to achieve full engagement of the ratchet teeth in the second and fourth locking surfaces is calculated. a :

[0078] θ a =i2θ hg ;

[0079] In the formula: θ a i1 represents the target rotation angle of the brushed motor, and i2 represents the transmission ratio of the interlaced helical gears.

[0080] If the angle sensor detects the actual rotation angle θ of the brushed motor t Less than the target rotation angle θ of the brushed motor a If the travel of the stationary disc is insufficient, it indicates that the ratchet between the second and fourth locking surfaces is not fully engaged, thus failing to meet the usage requirements. In this case, the EMB drive motor drives its spindle in the pressure relief direction to release pressure, adjusting the rotation by 1-2 degrees at a time. Simultaneously, the brushed motor continuously builds pressure until θ... t =θ aThis ensures that the ratchet teeth between the second locking surface and the fourth locking surface are fully engaged.

[0081] If the angle sensor detects the actual rotation angle θ of the brushed motor t Equal to the target rotation angle θ of the brushed motor a This indicates that the ratchet between the second locking surface and the fourth locking surface is fully engaged, meeting the parking requirements.

[0082] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0083] 1. The electromechanical parking mechanism of the present invention drives a helical gear to rotate via a brushed motor. While the helical gear rotates, it transmits power to the moving plate through a threaded transmission structure, thereby causing the moving plate to move axially. This causes the stationary plate to be clamped between the helical gear and the moving plate. Since a friction structure is provided between the first locking surface of the stationary plate and the third locking surface of the helical gear, and a ratchet structure is provided between the second locking surface of the stationary plate and the fourth locking surface of the moving plate, the stationary plate can be locked on both sides, thereby maintaining the parking force.

[0084] 2. In the electromechanical parking mechanism of the present invention, the threaded transmission between the worm gear and helical gear, and between the helical gear and the moving plate, all have a self-locking function, meaning they cannot be reversed. Therefore, after the parking pressure is built up, the brushed motor can stop driving, while the parking force can still be maintained. Compared with existing parking mechanisms that use solenoid valves as a power source, the electromechanical parking mechanism of the present invention does not require continuous power to maintain the parking force when parking, nor does it require continuous power to maintain the released parking state when driving. This greatly reduces power consumption and fundamentally solves the problem of high power consumption.

[0085] 3. Compared with parking mechanisms using ratchet and pawl structures, the electromechanical parking mechanism of the present invention adopts a double-sided locking method, which has a higher safety factor and reduces the risk of the pawl getting stuck in the ratchet due to spring failure during driving, which leads to automatic parking and vehicle brake failure or lock-up.

[0086] 4. The electromechanical parking mechanism of this invention, under the action of a brushed motor, simultaneously presses the stationary disc through the inner groove surface of the helical gear and the moving disc, forming double-sided pressure. This achieves a higher locking torque under the same clamping force, thus reducing the structural size of the double-sided locking mechanism and making it easier to deploy in EMB actuators, especially suitable for EMB systems in passenger vehicles. Simultaneously, ratchet teeth are provided on the contact surfaces between the moving and stationary discs, replacing the traditional knurled pattern. This not only increases the frictional torque but also ensures sufficient frictional torque is maintained even after the knurled pattern wears down, and also eliminates the risk of potential frictional failure after the knurled pattern wears out during use.

[0087] 5. The design method of the double-sided locking mechanism and the high-efficiency helical gear transmission of the electromechanical parking mechanism of the present invention can effectively reduce the size of the electromechanical parking mechanism of the present invention, making the deployment of the electromechanical parking mechanism of the present invention more convenient.

[0088] 6. The electromechanical parking mechanism of this invention uses interleaved helical gears (i.e., worm gears and helical gears) as the transmission mechanism, which features high mechanical efficiency, compact structure, and smooth transmission. Furthermore, the electromechanical parking mechanism of this invention can achieve linear control of the parking braking force, greatly simplifying the complexity of the control algorithm. It also does not require continuous power supply during driving (non-parking), thus effectively solving the energy consumption problem. In summary, the electromechanical parking mechanism of this invention has advantages such as compact structure, low energy consumption, fast response, and simple control, and is easy to deploy in EMB systems, possessing significant engineering significance and industrialization potential. Attached Figure Description

[0089] Figure 1 This is an exploded view of the electromechanical parking mechanism of the present invention.

[0090] Figure 2 This is a schematic diagram of the electromechanical parking mechanism of the present invention.

[0091] Figure 3 and Figure 4 This is a schematic diagram showing the installation of the static disk and the spline from two different perspectives.

[0092] Figure 5 This is a schematic diagram of the moving disk.

[0093] Figure 6 This is a schematic diagram of a helical gear.

[0094] Figure 7 This is a simplified structural diagram of the EMB system of the present invention.

[0095] Figure 8 This is a structural block diagram of the design method for the electromechanical parking mechanism of the present invention.

[0096] Figure 9 This is a control logic diagram of the control method for the electromechanical parking mechanism of the present invention. Detailed Implementation

[0097] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0098] Example 1

[0099] See Figures 1-6The electromechanical parking mechanism of the present invention includes a stationary disk 4 disposed on the main shaft 7 of an EMB drive motor and a double-sided locking mechanism for locking the stationary disk 4. The stationary disk 4 is fixedly connected to the main shaft 7 of the EMB drive motor. The double-sided locking mechanism includes a moving disk 5 and a linear drive mechanism for driving the moving disk 5 to perform linear motion. The linear drive mechanism includes a helical gear 3 and a rotary drive mechanism for driving the helical gear 3 to rotate. The helical gear 3 and the moving disk 5 are located on opposite sides of the stationary disk 4 and are coaxially arranged. The moving disk 5 is mounted on the housing via a sliding connection structure. The sliding connection structure is used to cause the moving disk 5 to move along the axial direction of the main shaft of the EMB drive motor 7. The helical gear 3 and the moving disk 5 are connected via a threaded transmission structure.

[0100] In this embodiment, the helical gear 3 is loosely connected to the main shaft of the EMB drive motor 7, allowing the helical gear 3 to rotate freely and translate axially on the main shaft of the EMB drive motor 7. Since brushed motors are low in cost and simple to control, the rotary drive mechanism in this embodiment includes a brushed motor 1 and a worm gear helical gear 2, wherein the worm gear helical gear 2 is mounted on the main shaft of the brushed motor 1, and the worm gear helical gear 2 and the helical gear 3 are arranged in a perpendicular and staggered meshing configuration.

[0101] See Figures 1-6 The stationary disc 4 has a first locking surface 402 and a second locking surface 401 on both sides, and the helical gear 3 has a third locking surface 301 at a position corresponding to the first locking surface 402. Both the first locking surface 402 and the third locking surface 301 are provided with knurled patterns, which can improve the static friction coefficient. The moving disc 5 has a fourth locking surface 501 at a position corresponding to the second locking surface 401, and both the second locking surface 401 and the fourth locking surface 501 are provided with ratchet teeth. The ratchet teeth can be used to increase friction, thereby preventing friction failure after the knurled patterns wear.

[0102] See Figures 1-6A spline 8 is provided between the stationary disk 4 and the main shaft of the EMB drive motor 7, and the spline 8 is mounted on the main shaft of the EMB drive motor 7; the stationary disk 4 is fixedly mounted on the spline 8; with the above configuration, when parking is required, the brushed motor 1 drives the worm gear helical gear 2 to drive the helical gear 3 to rotate, and the helical gear 3 drives the moving disk 5 to move in the direction of the helical gear 3 through the threaded transmission structure, that is, the helical gear 3 and the moving disk 5 move in opposite directions, thereby pressing the stationary disk 4 between the helical gear 3 and the moving disk 5, thereby realizing parking; when parking is required, the brushed motor 1 drives the worm gear helical gear 2 to drive the helical gear 3 to rotate in the opposite direction, thereby driving the moving disk 5 to move away from the direction of the helical gear 3, that is, the helical gear 3 and the moving disk 5 move in opposite directions, thereby causing the moving disk 5 and the helical gear 3 to release the stationary disk 4.

[0103] See Figures 1-6 The sliding connection structure includes multiple sets of anti-rotation limiting pins 6 disposed on the moving disk 5, and the multiple sets of anti-rotation limiting pins 6 are evenly arranged along the circumferential direction of the moving disk 5; the outer shell is provided with multiple sets of limiting holes that cooperate with the anti-rotation limiting pins 6; by setting the anti-rotation limiting pins 6, the moving disk 5 can be limited and guided, so that the moving disk 5 can only move axially under the drive of the helical gear 3.

[0104] See Figures 1-6 The threaded transmission structure includes an internal thread disposed in the inner cavity of the helical gear 3, the outer diameter of which is larger than the outer diameter of the stationary disk 4; an external thread that mates with the internal thread is disposed on the outer circumferential surface of the moving disk 5; in the initial state, the external thread and the internal thread are in a mating state; as the helical gear 4 continues to rotate and is limited by the anti-rotation limiting pin 6, the moving disk 5 can move axially, thereby moving towards or away from the helical gear 3, thereby locking or unlocking the stationary disk 4.

[0105] See Figures 1-6 The working principle of the electromechanical parking mechanism of the present invention is as follows:

[0106] When parking is required, the EMB drive motor 7 first builds up pressure until the pressure meets the parking requirements. Then, the brushed motor 1 drives the worm gear helical gear 2 to rotate, which in turn drives the helical gear 3. Since the rotating disk 5 is restricted from rotation by the anti-rotation limit pin 6, it can only move axially. Simultaneously, the rotating disk 5 and the helical gear 3 are connected by a threaded transmission. Therefore, under the continuous drive of the brushed motor 1, as the helical gear 3 continues to rotate, the helical gear 3 and the rotating disk 5 continuously press against the stationary disk 4 until the helical gear 3 and the rotating disk 5 simultaneously clamp both sides of the stationary disk 4. Because both the second locking surface 401 of the stationary disk 4 and the fourth locking surface 501 of the rotating disk 5 are equipped with ratchet structures, replacing the traditional knurled structure, frictional locking can be achieved when the ratchet teeth on the second locking surface 401 of the stationary disk 4 and the fourth locking surface 501 of the rotating disk 5 interlock, thus solving the potential risk of wear failure associated with the knurled structure. Since the static disk 4 and the main shaft of the EMB drive motor 7 are connected by a spline 8 to achieve torque transmission, parking force can be maintained, thereby realizing the parking function.

[0107] Furthermore, in controlling the electromechanical parking mechanism of the present invention, the rotation angle of the brushed motor 1 can be monitored in real time by an angle sensor, and then the axial movement distance of the moving plate 5 can be calculated to confirm whether the ratchet teeth on the second locking surface 401 in the stationary plate 4 and the fourth locking surface 501 in the moving plate 5 are fully engaged. If the rotation angle of the brushed motor 1 is insufficient, the spindle of the EMB drive motor 7 is driven to rotate in the opposite direction by an angle (i.e., compensation angle) using a fixed compensation method, while driving the brushed motor 1 to rotate, thereby achieving full engagement of the ratchet teeth on the second locking surface 401 in the stationary plate 4 and the fourth locking surface 501 in the moving plate 5.

[0108] When it is necessary to release the parking brake, the EMB drive motor 7 first stalls according to the driving torque required for parking; then the brushed motor 1 rotates in the opposite direction, thereby driving the worm gear 2 to drive the helical gear 3 to rotate in the opposite direction, so that the moving plate 5 and the helical gear 3 move away from the stationary plate 4, thereby realizing the release of the parking brake.

[0109] Example 2

[0110] See Figure 7The electromechanical braking system of the present invention includes a housing, an EMB drive motor mounted on the housing, a reducer assembly, a motion switching mechanism, and the electromechanical parking mechanism described in Embodiment 1. The reducer assembly transmits power from the EMB drive motor to the motion switching mechanism. The motion switching mechanism is a device that can convert between linear motion power and rotational motion power, typically a ball screw, trapezoidal screw, or sliding screw. The motion switching mechanism is installed inside the caliper and drives the caliper piston to perform linear motion to achieve braking or releasing the brake.

[0111] Example 3

[0112] See Figure 8 The design method of the electromechanical parking mechanism of the present invention includes the following steps:

[0113] Step S1: Calculate the clamping force required for parking and the parking brake torque required by the spindle of the EMB drive motor based on the vehicle information.

[0114] In this embodiment, the calculation process for the parking brake torque required by the spindle of the EMB drive motor is as follows:

[0115] Step S101: Calculate the parking braking torque N required for a single wheel of the vehicle using vehicle information (such as vehicle model, curb weight, etc.);

[0116] Step S102: Calculate the braking force F required for parking a single wheel of the vehicle by using the parking braking torque N required for a single wheel and the wheel braking radius b. b ;

[0117]

[0118] In the formula, σ is the safety factor for parking braking force, σ>1, and is generally taken as 1.2~1.5;

[0119] Step S103: Measure the required braking force F of the vehicle. b The friction coefficient μ1 between the brake disc and the piston is used to calculate the piston thrust F required by the EMB actuator when parking.

[0120]

[0121] When the EMB is parked, because the motion conversion mechanism does not have a self-locking function, there is a tendency for the motion conversion mechanism to be reversed, that is, the motion conversion mechanism will move in reverse; therefore, the motion conversion mechanism will reverse the torque through the reducer to drive the main shaft of the EMB drive motor.

[0122] Step S104: Calculate the torque N required to achieve the target parking thrust at the screw end using the piston thrust F output by the EMB actuator during parking and the screw lead L1. s ;

[0123]

[0124] In the formula: η1 represents the efficiency of the ball screw assembly, and η2 represents the mechanical efficiency of the EMB clamp assembly (including the thrust bearing);

[0125] Step S105: Maintain the torque N required at the lead screw input end when holding the parking thrust. s And the transmission ratio i1 of the EMB reducer assembly; calculate the torque N required by the spindle of the EMB drive motor. a ;

[0126]

[0127] Step S2: Based on the parking brake torque required by the spindle of the EMB drive motor, the ratchet parameters of the ratchet structure between the second locking surface of the stationary disc and the fourth locking surface of the moving disc are optimally designed; in this embodiment, the required torque N during parking is calculated. a Subsequently, the ratchet between the second and fourth locking surfaces needs to provide at least N. a The parking torque is used to maintain the vehicle in place. Simultaneously, because the moving plate is designed with an anti-rotation limit pin, the parking torque is transmitted from the stationary plate to the moving plate via ratchet teeth, and is ultimately maintained by the anti-rotation limit pin on the moving plate. Therefore, the design steps for the parameters of the ratchet teeth in the second locking surface of the stationary plate and the fourth locking surface of the moving plate are as follows:

[0128] Step S201: Calculate the frictional torque N required between the first locking surface of the stationary disc and the third locking surface of the helical gear. h ;

[0129]

[0130] Where: N d ξ1 is the rated torque of the brushed motor; μ2 is the coefficient of friction between the first locking surface of the stationary disc and the third locking surface of the helical gear; i2 is the transmission ratio between the staggered helical gears (i.e., the worm gear and the helical gear); ξ1 is the transmission efficiency between the staggered helical gears (i.e., the worm gear and the helical gear); r a η3 is the thread radius of the threaded transmission structure between the helical gear and the moving disk; η3 is the transmission efficiency of the threaded transmission structure between the helical gear and the moving disk.

[0131] Step S202: Determine the torque N required by the spindle of the EMB drive motor. aand the frictional torque N between the first locking surface of the stationary disc and the third locking surface of the helical gear. h Calculate the parking torque N required between the second locking surface of the stationary disc and the fourth locking surface of the moving disc. j ;

[0132] N j =N a -N h ;

[0133] Step S203: Based on the parking torque N j And the centripetal angle θ corresponding to a single ratchet, calculate the number of ratchet teeth C, and then calculate the torque N that each ratchet needs to bear. c ;

[0134]

[0135] Step S204: Based on the torque N required for each ratchet... c The radius R of the stationary disc and the radius r of the center hole of the stationary disc are calculated, where the radius r of the center hole of the stationary disc is determined by the spindle of the EMB drive motor; the shear force F borne by each ratchet tooth is calculated. c ;

[0136]

[0137] Step S205: Calculate the radial cross-sectional area S of each ratchet tooth using the radius R of the stationary disk, the radius r of the center hole of the stationary disk, and the number of ratchet teeth C.

[0138]

[0139] Step S206: Determine the radial cross-sectional area S of each ratchet tooth, and determine the shear force F borne by each ratchet tooth. c Calculate the shear strength τ1 borne by each ratchet tooth;

[0140]

[0141] Step S207: Apply a safety constraint to the shear strength τ1 borne by each ratchet, i.e.:

[0142] τ1≤Kτ allow ;

[0143] In the formula: τ allow This represents the allowable shear strength of the materials for the moving and stationary disks, where K represents the safety factor, and K < 1.

[0144] Step S208: Construct the minimum static disk radius calculation model:

[0145]

[0146] Under the premise of satisfying safety constraints, the calculation model for the minimum static disk radius is solved to obtain the minimum static disk radius R.

[0147] Step S3: Design the parameters of the anti-rotation limit pin on the moving plate according to the parking brake torque required by the spindle of the EMB drive motor.

[0148] In this embodiment, the parking torque is ultimately maintained by the anti-rotation limit pins on the moving plate. Therefore, the size and number of these anti-rotation limit pins need to be selected and designed according to the required braking force of the vehicle model. Thus, the steps for designing the parameters of the anti-rotation limit pins on the moving plate are as follows:

[0149] Step S301: The torque N required for the spindle of the motor driven by the EMB is determined. a Given the number of anti-rotation limit pins k, calculate the torque N required for each anti-rotation limit pin on the drive disc. k ;

[0150]

[0151] Step S302: The torque N required to be provided by each anti-rotation limit pin on the moving plate. k Calculate the shear force F acting on each anti-rotation limit pin on the moving plate by taking the distance D from the center of the axis of each anti-rotation limit pin to the center of the axis of the moving plate. k ;

[0152]

[0153] Step S303: Based on the shear force F exerted on each anti-rotation limit pin on the moving disc... k Given the cross-sectional area A of the anti-rotation limiting pin, calculate the shear strength τ of the anti-rotation limiting pin. k ;

[0154]

[0155] In the formula: d represents the diameter of the anti-rotation limit pin;

[0156] Step S304: To ensure that the anti-rotation limit pins meet the shear requirements of the parking torque, select a pin diameter that conforms to the standard (such as the cylindrical pin specifications specified in GB / T 118 or ISO standards); determine the shear strength τ of each anti-rotation limit pin. k Apply safety constraints, namely:

[0157]

[0158] In the formula: τ allowThis represents the allowable shear strength of the material, and K represents the safety factor, where K < 1;

[0159] Step S305: Construct the minimum diameter model of the anti-rotation limit pin;

[0160]

[0161] Under the premise of meeting safety constraints, the minimum diameter model of the anti-rotation limit pin is solved to calculate the minimum diameter d of the anti-rotation limit pin.

[0162] Example 4

[0163] See Figure 9 The control method for the electromechanical parking mechanism of the present invention includes the following steps:

[0164] Step 1: When the EMB is used for parking, the EMB drive motor drives the spindle to build up an initial parking pressure F2 that is greater than the actual required parking pressure F1.

[0165] F2 = x1F1;

[0166] In the formula: x1 represents the number of times the parking force that the EMB drive motor needs to initially establish is greater than the theoretically calculated parking force. x1 > 1 and is generally taken as 1.2-1.5; F1 represents the theoretically calculated parking force, which is selected by calculation based on the specific vehicle model.

[0167] Step 2: The brushed motor drives the worm gear to rotate, which in turn drives the staggered helical gear pair to rotate. While the helical gears are rotating, the moving disk is driven to move axially through the threaded transmission structure, thereby clamping the stationary disk between the helical gears and the moving disk.

[0168] Step 3: The rotation angle of the brushed motor is detected by an angle sensor installed on the brushed motor, and the axial movement stroke of the stationary disc is calculated to determine whether the ratchet on the stationary disc and the ratchet on the moving disc are fully engaged.

[0169] Specifically, the required rotation angle θ of the helical gear is calculated based on the travel of the moving disc when the ratchet pairs of the second and fourth locking surfaces are fully engaged. hg :

[0170]

[0171] In the formula: x2 represents the axial movement distance of the moving plate when stable parking is achieved, i.e., when the ratchet on the stationary plate is fully engaged with the ratchet on the moving plate; L2 represents the pitch of the threaded transmission structure between the helical gear and the moving plate; θ hg Indicates the target rotation angle of the helical gear;

[0172] Next, based on the transmission ratio of the interleaved helical gears, the target rotation angle θ required for the brushed motor shaft to rotate to achieve full engagement of the ratchet teeth in the second and fourth locking surfaces is calculated. a :

[0173] θ a =i2θ hg ;

[0174] In the formula: θ a i1 represents the target rotation angle of the brushed motor, and i2 represents the transmission ratio of the interlaced helical gears.

[0175] If the angle sensor detects the actual rotation angle θ of the brushed motor t Less than the target rotation angle θ of the brushed motor a If the travel of the stationary disc is insufficient, it indicates that the ratchet between the second and fourth locking surfaces is not fully engaged, thus failing to meet the usage requirements. In this case, the EMB drive motor drives its spindle in the pressure relief direction to release pressure, adjusting the rotation by 1-2 degrees at a time. Simultaneously, the brushed motor continuously builds pressure until θ... t =θ a This ensures that the ratchet teeth between the second locking surface and the fourth locking surface are fully engaged.

[0176] If the angle sensor detects the actual rotation angle θ of the brushed motor t Equal to the target rotation angle θ of the brushed motor a This indicates that the ratchet between the second locking surface and the fourth locking surface is fully engaged, meeting the parking requirements.

[0177] The above are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An electromechanical parking mechanism, characterized in that, It includes a stationary disc mounted on the spindle of the EMB drive motor and a double-sided locking mechanism for locking the stationary disc, wherein, The static disk is fixedly connected to the main shaft of the EMB drive motor; The double-sided locking mechanism includes a movable disk and a linear drive mechanism for driving the movable disk to perform linear motion. The linear drive mechanism includes a helical gear and a rotary drive mechanism for driving the helical gear to rotate. The helical gear and the movable disk are located on opposite sides of the stationary disk and are coaxially arranged. The movable disk is mounted on the housing via a sliding connection structure. The sliding connection structure enables the movable disk to move along the axial direction of the main shaft of the EMB drive motor. The helical gear and the movable disk are connected via a threaded transmission structure. A friction structure is provided between the helical gear and the stationary disk, and a ratchet structure is provided between the moving disk and the stationary disk; The rotary drive mechanism includes a brushed motor and a worm gear, wherein the worm gear is mounted on the spindle of the brushed motor, and the worm gear and the helical gear are meshed in a perpendicularly staggered arrangement; The stationary disc has a first locking surface and a second locking surface on both sides, and the helical gear has a third locking surface at a position corresponding to the first locking surface; the friction structure includes knurled patterns respectively provided on the first locking surface and the third locking surface; the moving disc has a fourth locking surface at a position corresponding to the second locking surface, and the ratchet structure includes ratchet teeth respectively provided on the second locking surface and the fourth locking surface; A spline is provided between the stationary disk and the spindle of the EMB drive motor, and the spline is fixedly mounted on the spindle of the EMB drive motor; the stationary disk is fixedly mounted on the spline. The sliding connection structure includes multiple sets of anti-rotation limiting pins disposed on the moving plate, and the multiple sets of anti-rotation limiting pins are evenly arranged along the circumferential direction of the moving plate; the outer shell is provided with multiple sets of limiting holes that cooperate with the anti-rotation limiting pins. The threaded transmission structure includes an internal thread disposed in the inner cavity of the helical gear, the outer diameter of the internal thread being larger than the outer diameter of the stationary disc; an external thread that mates with the internal thread is disposed on the outer circumferential surface of the moving disc; in the initial state, the external thread and the internal thread are in a mating state.

2. A design method for the electromechanical parking mechanism as described in claim 1, characterized in that, Includes the following steps: Step S1: Calculate the clamping force required for parking and the parking braking torque required by the EMB drive motor spindle based on vehicle information; the calculation process for the parking braking torque required by the EMB drive motor spindle is as follows: Step S101: Calculate the parking braking torque N required for a single wheel of the vehicle based on the vehicle information; Step S102: Calculate the braking force F required for parking a single wheel of the vehicle by using the parking braking torque N required for a single wheel and the wheel braking radius b. b : In the formula, σ is the parking braking force safety factor, σ>1, and the value range is [1.2, 1.5]; Step S103: Measure the required braking force F of the vehicle. b The friction coefficient μ1 between the brake disc and the piston is used to calculate the piston thrust F required by the EMB actuator when parking. Step S104: Calculate the torque N required to achieve the target parking thrust at the screw end using the piston thrust F of the EMB during parking and the lead screw lead L1. s ; In the formula: η1 represents the efficiency of the ball screw assembly, and η2 represents the efficiency of the EMB clamp assembly; Step S105: Maintain the torque N required at the lead screw input end when holding the parking thrust. s And the transmission ratio i1 of the EMB reducer assembly; The torque N required by the spindle of the EMB drive motor is calculated. a ; Step S2: Based on the parking brake torque required by the spindle of the EMB drive motor, optimize the ratchet parameters of the ratchet structure between the second locking surface of the stationary disc and the fourth locking surface of the moving disc. Step S3: Design the parameters of the anti-rotation limit pin on the moving plate according to the parking brake torque required by the spindle of the EMB drive motor.

3. The design method of the electromechanical parking mechanism according to claim 2, characterized in that, In step S2, the design steps for the ratchet parameters of the ratchet structure in the second locking surface of the stationary disk and the fourth locking surface of the moving disk are as follows: Step S201: Calculate the frictional torque N required between the first locking surface of the stationary disc and the third locking surface of the helical gear. h ; Where: N d ξ1 is the rated torque of the brushed motor; μ2 is the coefficient of friction between the first locking surface of the stationary disc and the third locking surface of the helical gear; i2 is the transmission ratio between the interlaced helical gears; ξ1 is the transmission efficiency between the interlaced helical gears; r a η3 is the thread radius of the threaded transmission structure between the helical gear and the moving disk; η3 is the transmission efficiency of the threaded transmission structure between the helical gear and the moving disk. Step S202: Determine the torque N required by the spindle of the EMB drive motor. a and the frictional torque N between the first locking surface of the stationary disc and the third locking surface of the helical gear. h Calculate the parking torque N required between the second locking surface of the stationary disc and the fourth locking surface of the moving disc. j ; N j =N a -N h ; Step S203: Based on the parking torque N j And the centripetal angle θ corresponding to a single ratchet, calculate the number of ratchet teeth C, and then calculate the torque N that each ratchet needs to bear. c ; Step S204: Based on the torque N required for each ratchet... c The radius R of the stationary disc and the radius r of the center hole of the stationary disc are calculated, where the radius r of the center hole of the stationary disc is determined by the spindle of the EMB drive motor; the shear force F borne by each ratchet tooth is calculated. c ; Step S205: Calculate the radial cross-sectional area S of each ratchet tooth using the radius R of the stationary disk, the radius r of the center hole of the stationary disk, and the number of ratchet teeth C. Step S206: Determine the radial cross-sectional area S of each ratchet tooth, and determine the shear force F borne by each ratchet tooth. c Calculate the shear strength τ1 borne by each ratchet tooth; Step S207: Apply a safety constraint to the shear strength τ1 borne by each ratchet, i.e.: τ1≤Kτ a ; In the formula: τ a This represents the allowable shear strength of the materials for the moving and stationary disks, where K represents the safety factor, and K < 1. Step S208: Construct the minimum static disk radius R m Computational model: Under the premise of satisfying safety constraints, the calculation model for the minimum static disk radius is solved to obtain the minimum static disk radius R. m .

4. The design method of the electromechanical parking mechanism according to claim 2, characterized in that, In step S3, the steps for designing the parameters of the anti-rotation limit pin on the moving disk are as follows: Step S301: The torque N required for the spindle of the motor driven by the EMB is determined. a Given the number of anti-rotation limit pins k, calculate the torque N required for each anti-rotation limit pin on the drive disc. k ; Step S302: The torque N required to be provided by each anti-rotation limit pin on the moving plate. k Calculate the shear force F acting on each anti-rotation limit pin on the moving plate by taking the distance D from the center of the axis of each anti-rotation limit pin to the center of the axis of the moving plate. k ; Step S303: Based on the shear force F exerted on each anti-rotation limit pin on the moving disc... k Given the cross-sectional area A of the anti-rotation limiting pin, calculate the shear strength τ of the anti-rotation limiting pin. k ; In the formula: d represents the diameter of the anti-rotation limit pin; Step S304: The shear strength τ of each anti-rotation limit pin k Apply safety constraints, namely: t k ≤Kτ allow ; In the formula: τ allow K represents the allowable shear strength of the material of the anti-rotation limit pin, K represents the safety factor, and K < 1; Step S305: Construct a calculation model for the minimum diameter of the anti-rotation limit pin; Under the premise of meeting safety constraints, the minimum diameter model of the anti-rotation limiting pin is solved to calculate the minimum diameter d of the anti-rotation limiting pin. m .

5. A control method for the electromechanical parking mechanism as described in claim 1, characterized in that, Includes the following steps: Step 1: When the EMB is used for parking, the EMB drive motor drives the spindle to build up an initial parking pressure F2 that is greater than the actual required parking pressure F1. F2 = x1F1; In the formula: x1 represents the number of times the parking force that the EMB drive motor needs to initially establish is greater than the theoretically calculated parking force; F1 represents the theoretically calculated parking force, which is selected by the specific vehicle model; x1 > 1, and its value ranges from 1.2 to 1.

5. Step 2: The brushed motor drives the worm gear to rotate, which in turn drives the helical gear to rotate. At the same time, the rotation of the helical gear drives the moving plate to move axially through the threaded transmission structure, thereby clamping the stationary plate between the helical gear and the moving plate. Step 3: The rotation angle of the brushed motor is detected by an angle sensor installed on the brushed motor, and the axial movement stroke of the moving plate is calculated to determine whether the ratchet on the stationary plate and the ratchet on the moving plate are fully engaged. Specifically, the required rotation angle θ of the helical gear is calculated based on the travel of the moving disc when the ratchet pairs of the second and fourth locking surfaces are fully engaged. hg : In the formula: x2 represents the axial movement distance of the moving plate when stable parking is achieved, i.e., when the ratchet on the stationary plate is fully engaged with the ratchet on the moving plate; L2 represents the pitch of the threaded transmission structure between the helical gear and the moving plate; θ hg Indicates the target rotation angle of the helical gear; Next, based on the transmission ratio of the interleaved helical gears, the target rotation angle θ required for the brushed motor shaft to rotate to achieve full engagement of the ratchet teeth in the second and fourth locking surfaces is calculated. a : i a =i2θ hg ; In the formula: θ a i1 represents the target rotation angle of the brushed motor, and i2 represents the transmission ratio of the interlaced helical gears. If the angle sensor detects the actual rotation angle θ of the brushed motor t Less than the target rotation angle θ of the brushed motor a If the travel of the stationary disc is insufficient, it indicates that the ratchet between the second and fourth locking surfaces is not fully engaged, thus failing to meet the usage requirements. In this case, the EMB drive motor drives its spindle in the pressure relief direction to release pressure, adjusting the rotation by 1-2 degrees at a time. Simultaneously, the brushed motor continuously builds pressure until θ... t =θ a This ensures that the ratchet teeth between the second locking surface and the fourth locking surface are fully engaged. If the angle sensor detects the actual rotation angle θ of the brushed motor t Equal to the target rotation angle θ of the brushed motor a This indicates that the ratchet between the second locking surface and the fourth locking surface is fully engaged, meeting the parking requirements.

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