Electromechanical parking mechanism, design method and control method

Abstract

The invention discloses an electronic mechanical parking mechanism, a design method and a control method. The electronic mechanical parking mechanism comprises a static disc arranged on a main shaft of the EMB driving motor and a double-face locking mechanism. The static disc is fixedly connected to a main shaft of the EMB driving motor; the double-sided locking mechanism comprises a movable disc and a linear driving mechanism; the linear driving mechanism comprises a helical gear and a rotary driving mechanism; the bevel gear and the movable disc are located on the two sides of the static disc respectively. The movable disc is connected to the shell in a sliding mode. The helical gear is connected with the movable disc through a thread transmission structure; the rotary driving mechanism comprises a brush motor and a worm helical gear; the worm helical gear is installed on a main shaft of the brush motor, and the worm helical gear and the helical gear are meshed to form vertical staggered arrangement. According to the electronic mechanical parking mechanism, a double-face locking mode is adopted, the safety coefficient is higher, and the risk of vehicle braking failure or locking in the running process is lower.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle brake control, and in particular relates to an electronic mechanical parking mechanism, a design method and a control method. Background Art

[0002] The wire-controlled chassis is the guarantee for the implementation of high-level autonomous driving technology. The electronic mechanical brake system (EMB) completely abandons hydraulic / pneumatic devices and is a pure wire-controlled brake system in the true sense. It realizes the decoupling of people and vehicles, is easy to integrate parking functions, improves the active safety and handling stability of vehicles, and is an ideal brake actuator for high-level autonomous driving technology. The electronic mechanical brake system (EMB) uses the motor as the driving force output of the brake, and decelerates and increases the torque through the reducer component to output the required braking force. Then, the rotational motion needs to be converted into linear translation through the motion conversion mechanism to push the brake pads of the caliper to lock the brake disc to achieve braking; among them, the ball screw is considered to be an effective solution as a motion conversion mechanism for the electronic mechanical brake system (EMB) due to its high transmission efficiency, long life and high transmission accuracy.

[0003] It is worth noting that the ball screw pair does not have a self-locking function and cannot maintain the braking force when deployed on the EMB. Therefore, in order to realize the parking and temporary parking functions of the electronic mechanical brake system (EMB), it is necessary to deploy a parking mechanism on the assembly of the electronic mechanical brake system (EMB). Specifically, the parking mechanism assists the EMB to provide sufficient parking force for the vehicle, and it cannot decay. At present, although researchers have proposed many EMB parking mechanisms, the existing technical solutions are not yet mature, and there are still many problems that need to be solved; among them, in terms of structure, the principles of the existing public EMB parking mechanisms are mainly divided into ratchet pawl combined with solenoid valve type and wedge friction disc combined with solenoid valve type. For example, the utility model patent with authorization publication number CN221800560U and the utility model patent with authorization publication number CN221610450U both demonstrate a friction disc type EMB parking mechanism; while the invention patent application with application publication number CN 117905879 A and the utility model patent with authorization publication number CN219115422 U disclose a ratchet pawl type EMB parking mechanism. It is worth noting that the ratchet pawl parking mechanism has the problem of being difficult to control the pawl to fall accurately into the target ratchet groove when parking, so that accurate locking cannot be achieved, and there is a high risk of slipping due to insufficient parking brake force. At present, there is still no effective control method for accurately dropping the pawl into the target ratchet groove. In addition, the ratchet pawl parking mechanism generally uses an elastic element to pull the pawl when not parking. During driving, the harsh vibration environment easily causes the elastic element to break and fail, causing the pawl to get stuck in the ratchet teeth during driving, which in turn causes the risk of vehicle locking or EMB driving brake failure, such as the "Electronic Mechanical Parking Self-locking Mechanism, Control Method and Vehicle" disclosed in the invention patent application with application publication number CN117905879 A. The existing wedge friction disc combined with solenoid valve actuator is large in size and difficult to deploy on the EMB assembly, especially for passenger cars with limited space. The friction disc parking mechanism usually uses a knurling pattern to achieve friction braking, but the knurling pattern is prone to wear and failure after a period of use, which is a high risk. At the same time, most of the existing parking mechanisms use solenoid valves as the power source of the parking mechanism. The solenoid valves need to remain energized when the vehicle is in driving state (i.e., not parking). This makes solving the energy consumption of the entire vehicle another major problem. The design requirements in terms of safety and energy consumption are not met, so it is difficult to actually apply them in industry. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides an electronic mechanical parking mechanism, which adopts a double-sided locking method, has a higher safety factor, lower energy consumption, is more convenient to deploy on an EMB actuator, and has a lower risk of vehicle brake failure or locking during driving.

[0005] A second object of the present invention is to provide a design method for an electronic mechanical parking mechanism.

[0006] A third object of the present invention is to provide a control method for an electronic mechanical parking mechanism.

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

[0008] An electromechanical parking mechanism comprises a static plate arranged on the main shaft of an EMB drive motor and a double-sided locking mechanism for locking the static plate, 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 moving plate and a linear driving mechanism for driving the moving plate to perform linear motion, wherein the linear driving mechanism includes a helical gear and a rotary driving mechanism for driving the helical gear to rotate; the helical gear and the moving plate are respectively located on both sides of the static plate, and the three are coaxially arranged; the moving plate is mounted on the housing through a sliding connection structure; the sliding connection structure is used to enable the moving plate to move along the axial direction of the main shaft of the EMB drive motor; the helical gear and the moving plate are connected through a threaded transmission structure;

[0011] A friction structure is provided between the helical gear and the static plate, and a ratchet structure is provided between the dynamic plate and the static plate;

[0012] The rotary drive mechanism comprises a brushed motor and a worm bevel gear, wherein the worm bevel gear is mounted on the main shaft of the brushed motor, and the worm bevel gear is meshed with the bevel gear in a vertically staggered arrangement.

[0013] Furthermore, a first locking surface and a second locking surface are respectively provided on both sides of the stationary plate, wherein the bevel 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 movable plate is provided with a fourth locking surface at a position corresponding to the second locking surface, and the ratchet structure includes ratchets respectively provided on the second locking surface and the fourth locking surface.

[0014] Furthermore, a spline is provided between the stator plate and the main shaft of the EMB drive motor, and the spline is fixedly mounted on the main shaft of the EMB drive motor; and the stator plate is fixedly mounted on the spline.

[0015] Furthermore, the sliding connection structure includes a plurality of groups of stop-rotation limit pins arranged on the moving disk, and the plurality of groups of stop-rotation limit pins are evenly arranged along the circumferential direction of the moving disk; and the outer shell is provided with a plurality of groups of limit holes cooperating with the stop-rotation limit pins.

[0016] Furthermore, the threaded transmission structure includes an internal thread arranged in the inner cavity of the bevel gear, and the outer diameter of the internal thread is larger than the outer diameter of the static plate; an external thread matching the internal thread is arranged on the outer circumferential surface of the dynamic plate; in an initial state, the external thread and the internal thread are in a matching state.

[0017] A design method for an electronic mechanical parking mechanism comprises the following steps:

[0018] Step S1: Calculate the clamping force required for parking and the parking brake torque required to be provided by the main shaft of the EMB drive motor according to the vehicle information;

[0019] Step S2: optimally designing the ratchet parameters of the ratchet structure between the second locking surface of the static plate and the fourth locking surface of the dynamic plate according to the parking brake torque required to be provided by the main shaft of the EMB drive motor;

[0020] Step S3: Design the parameters of the stop pin on the moving plate according to the parking brake torque required to be provided by the main shaft of the EMB drive motor.

[0021] Furthermore, in step S1, the calculation process of the parking brake torque required to be provided by the main shaft of the EMB drive motor is:

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

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

[0024]

[0025] Where, σ is the parking brake force safety factor, σ>1, and the value range is [1.2, 1.5];

[0026] Step S103: The required braking force F of the vehicle b and the friction coefficient μ1 of the brake disc, the piston thrust F output by the EMB actuator required for parking is calculated;

[0027]

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

[0029]

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

[0031] Step S105: The torque N required at the screw input end when maintaining the parking thrust s And the transmission ratio i1 of the EMB reducer assembly; calculate the torque N that the main shaft of the EMB drive motor needs to provide a ;

[0032]

[0033] Further, in step S2, the design steps of the ratchet parameters of the ratchet structure in the second locking surface of the static plate and the fourth locking surface of the dynamic plate are:

[0034] Step S201: Calculate the friction torque N required between the first locking surface of the stator plate and the third locking surface of the bevel gear. h ;

[0035]

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

[0037] Step S202: The torque N required to be provided by the main shaft of the EMB driving motor a And the friction torque N between the first locking surface of the stator plate and the third locking surface of the bevel gear h , calculate the parking torque N required between the second locking surface of the static plate and the fourth locking surface of the dynamic plate j ;

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

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

[0040]

[0041]

[0042] Step S204: According to the torque N that each ratchet needs to bear c , the radius R of the static disk and the radius r of the center hole of the static disk, where the radius r of the center hole of the static disk is determined by the main shaft of the EMB drive motor; calculate the shear force F borne by each ratchet c ;

[0043]

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

[0045]

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

[0047]

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

[0049]

[0050] Where: τ allow It indicates the allowable shear strength of the materials of the moving plate and the static plate, K indicates the safety factor, and K is less than 1;

[0051] Step S208: Constructing a minimum static disk radius calculation model:

[0052]

[0053] Under the premise of satisfying the safety constraints, the constructed minimum static disk radius calculation model 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 movable plate is:

[0055] Step S301: The torque N required by the main shaft of the motor driven by the EMB aand the number of stop pins k, calculate the torque N required for each stop pin on the moving plate k ;

[0056]

[0057] Step S302: The torque N required to be provided by each stop pin on the moving plate k And the distance D from the center axis of each stop pin to the center axis of the moving plate, calculate the shear force F on each stop pin on the moving plate k ;

[0058]

[0059] Step S303: According to the shear force F exerted on each stop-rotation limit pin on the moving plate k and the cross-sectional area A of the stop pin, calculate the shear strength τ of the stop pin k ;

[0060]

[0061] Where: d represents the diameter of the stop pin;

[0062] Step S304: The shear strength τ of each stop pin k Imposing safety constraints, namely:

[0063] τ k ≤Kτ allow ;

[0064] Where: τ allow Indicates the allowable shear strength of the material of the stop pin, K indicates the safety factor, and K < 1;

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

[0066]

[0067] Under the premise of meeting the safety constraints, the constructed minimum diameter model of the stop pin is solved to calculate the minimum diameter d of the stop pin.

[0068] A control method for an electronic mechanical parking mechanism comprises the following steps:

[0069] Step 1: When the EMB builds up pressure to park, the EMB drives the motor to drive the spindle to build up a preliminary parking pressure F2 that is greater than the actual required parking pressure F1;

[0070] F2 = x1F1;

[0071] Where: x1 indicates that the parking force that the EMB drive motor needs to initially establish is a multiple of the theoretically calculated parking force, F1 indicates the theoretically calculated parking force, and this value is selected by the specific vehicle model; x1>1, and its value range is 1.2-1.5;,

[0072] Step 2: The brushed motor drives the worm helical gear to rotate, thereby driving the helical gear to rotate. While the helical gear rotates, the threaded transmission structure drives the moving plate to move axially, thereby clamping the static plate between the helical gear and the moving plate;

[0073] Step 3: Detect the rotation angle of the brushed motor by using the angle sensor installed on the brushed motor to calculate the axial movement stroke of the moving plate, and then determine whether the ratchet teeth on the stationary plate and the ratchet teeth on the moving plate are completely embedded;

[0074] The required rotation angle θ of the helical gear is calculated based on the moving stroke of the movable plate when the ratchet teeth of the second locking surface and the fourth locking surface are fully engaged. hg :

[0075]

[0076] Where: x2 represents the distance the moving plate moves axially when stable parking is achieved, that is, when the ratchet teeth on the static plate and the ratchet teeth on the moving plate are fully embedded; 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, the target rotation angle θ of the motor shaft of the brushed motor required to rotate when the ratchet teeth in the second locking surface and the fourth locking surface are fully engaged is calculated according to the transmission ratio of the staggered helical gears. a :

[0078] θ a =i2θ hg ;

[0079] Where: θ a represents the target rotation angle of the brushed motor, and i2 represents the transmission ratio of the staggered helical gears;

[0080] If the angle sensor detects the actual rotation angle θ of the brushed motor t Smaller than the target rotation angle θ of the brushless motor a , it indicates that the travel of the static disk is insufficient, and the ratchet teeth between the second locking surface and the fourth locking surface are not completely embedded, that is, they cannot meet the use requirements. At this time, the EMB drive motor drives its main shaft to the pressure relief direction to relieve pressure, and rotates and adjusts at an angle of 1 degree to 2 degrees at a time. At the same time, the brush motor continuously builds pressure until θ t =θ a, so that the ratchet teeth between the second locking surface and the fourth locking surface are completely embedded;

[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 , it indicates that the ratchet teeth between the second locking surface and the fourth locking surface have been completely embedded, meeting the parking requirements.

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

[0083] 1. The electronic mechanical parking mechanism of the present invention drives the helical gear to rotate through a brushed motor, and while the helical gear rotates, the power is transmitted to the movable plate through a threaded transmission structure, thereby driving the movable plate to make axial movement, so as to cause the static plate to be clamped between the helical gear and the movable plate. Among them, since a friction structure is provided between the first locking surface of the static plate and the third locking surface of the helical gear, and a ratchet structure is provided between the second locking surface of the static plate and the fourth locking surface of the movable plate, it is possible to achieve double-sided locking of the static plate, thereby maintaining the parking force.

[0084] 2. The threaded transmission between the worm and the helical gear, and between the helical gear and the moving plate in the electronic mechanical parking mechanism of the present invention has a self-locking function, that is, it cannot be reversely driven. Therefore, after the pressure is built up for parking, the brushed motor can stop driving, and the parking force can still be maintained. Compared with the existing parking mechanism using a solenoid valve as a power source, the electronic mechanical parking mechanism of the present invention does not need to be continuously powered on to maintain the parking force when parking, and does not need to be continuously powered on to maintain the parking release state when driving. This can greatly reduce power consumption and fundamentally solve the problem of high power consumption.

[0085] 3. Compared with the parking mechanism using a ratchet and pawl structure, the electronic mechanical 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 being trapped in the ratchet due to spring failure during driving, thereby causing automatic parking and resulting in vehicle brake failure or locking.

[0086] 4. Under the action of the brushed motor, the electronic mechanical parking mechanism of the present invention squeezes the static plate through the inner groove surface of the helical gear and the dynamic plate at the same time, forming a double-sided pressure build-up, achieving a higher locking torque under the same clamping force, which can reduce the structure of the double-sided locking mechanism, making it more convenient to deploy in the EMB actuator, and is particularly suitable for the EMB system of passenger cars. At the same time, ratchets are provided on the contact surface between the dynamic plate and the static plate to replace the traditional knurling pattern; this not only increases the friction torque, but also ensures that sufficient friction torque can be maintained after the knurling pattern is worn, and also solves the risk of potential friction failure of the knurling pattern after use and wear.

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

[0088] 6. The electronic mechanical parking mechanism of the present invention uses staggered helical gears (i.e., worm helical gears and helical gears) as a transmission mechanism, which has the characteristics of high mechanical efficiency, compact structure, and smooth transmission; in addition, the electronic mechanical parking mechanism of the present invention can realize linear control of the parking brake force, which greatly simplifies the complexity of the control algorithm, and does not require continuous power supply during driving (non-parking), thereby solving the energy consumption problem well; in summary, the electronic mechanical parking mechanism of the present invention has the advantages of compact structure, low energy consumption, fast response, simple control, etc., and is easy to deploy and apply in the EMB system, and has great engineering significance and industrialization vision. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 It is a structural exploded view of the electronic mechanical parking mechanism of the present invention.

[0090] Figure 2 It is a structural schematic diagram of the electronic mechanical parking mechanism of the present invention.

[0091] Figure 3 and Figure 4 The diagram shows the installation of the stator and spline from two different perspectives.

[0092] Figure 5 It is a structural diagram of the moving disk.

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

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

[0095] Figure 8 It is a structural block diagram of the design method of the electronic mechanical parking mechanism of the present invention.

[0096] Fig. 9 It is a control logic diagram of the control method of the electronic mechanical parking mechanism of the present invention. DETAILED DESCRIPTION

[0097] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0098] Example 1

[0099] See also Figure 1-Figure 6The electronic mechanical parking mechanism of the present invention comprises a static plate 4 arranged on the main shaft 7 of the EMB drive motor and a double-sided locking mechanism for locking the static plate 4, wherein the static plate 4 is fixedly connected to the main shaft 7 of the EMB drive motor; the double-sided locking mechanism comprises a dynamic plate 5 and a linear driving mechanism for driving the dynamic plate 5 to perform linear motion, wherein the linear driving mechanism comprises a bevel gear 3 and a rotary driving mechanism for driving the bevel gear 3 to rotate; the bevel gear 3 and the dynamic plate 5 are respectively located on both sides of the static plate 4, and the three are coaxially arranged; the dynamic plate 5 is installed on the housing through a sliding connection structure; the sliding connection structure is used to cause the dynamic plate 5 to move along the axial direction of the main shaft of the EMB drive motor 7; the bevel gear 3 and the dynamic plate 5 are connected through a threaded transmission structure;

[0100] In this embodiment, the bevel gear 3 is loosely connected to the main shaft of the EMB drive motor 7, so that the bevel gear 3 can freely rotate and axially translate on the main shaft of the EMB drive motor 7; since the brush motor has low cost and simple control, the rotary drive mechanism in this embodiment includes a brush motor 1 and a worm bevel gear 2, wherein the worm bevel gear 2 is installed on the main shaft of the brush motor 1, and the worm bevel gear 2 and the bevel gear 3 form a vertically staggered arrangement and meshing.

[0101] See also Figure 1-Figure 6 , a first locking surface 402 and a second locking surface 401 are respectively provided on both sides of the static plate 4, wherein the bevel gear 3 is provided with a third locking surface 301 at a position corresponding to the first locking surface 402; the first locking surface 402 and the third locking surface 301 are both provided with knurling patterns, and the static friction coefficient can be improved by providing the knurling patterns; the movable plate 5 is provided with a fourth locking surface 501 at a position corresponding to the second locking surface 401, and the second locking surface 401 and the fourth locking surface 501 are both provided with ratchet teeth; the ratchet teeth can be used to increase friction, thereby preventing friction failure after the knurling pattern is worn.

[0102] See also Figure 1-Figure 6A spline 8 is provided between the static plate 4 and the main shaft of the EMB drive motor 7, and the spline 8 is installed on the main shaft of the EMB drive motor 7; the static plate 4 is fixedly installed on the spline 8; through the above arrangement, when parking is required, the brush motor 1 drives the worm bevel gear 2 to drive the bevel gear 3 to rotate, and the bevel gear 3 drives the movable plate 5 to move in the direction of the bevel gear 3 through the threaded transmission structure, that is, the bevel gear 3 and the movable plate 5 move in opposite directions, thereby pressing the static plate 4 between the bevel gear 3 and the movable plate 5, so as to achieve parking; when parking needs to be released, the brush motor 1 drives the worm bevel gear 2 to drive the bevel gear 3 to rotate in the opposite direction, thereby driving the movable plate 5 to move away from the bevel gear 3, that is, the bevel gear 3 and the movable plate 5 move in the opposite direction, and then the movable plate 5 and the bevel gear 3 release the static plate 4.

[0103] See also Figure 1-Figure 6 The sliding connection structure includes a plurality of groups of stop-rotation limit pins 6 arranged on the moving plate 5, and the plurality of groups of stop-rotation limit pins 6 are evenly arranged along the circumferential direction of the moving plate 5; a plurality of groups of limit holes cooperating with the stop-rotation limit pins 6 are arranged on the outer shell; by setting the stop-rotation limit pins 6, the moving plate 5 can be limited and guided, so that the moving plate 5 can only make axial movement under the drive of the bevel gear 3.

[0104] See also Figure 1-Figure 6 The threaded transmission structure includes an internal thread arranged in the inner cavity of the bevel gear 3, and the outer diameter of the internal thread is larger than the outer diameter of the static plate 4; the outer circumferential surface of the movable plate 5 is provided with an external thread matching the internal thread; in the initial state, the external thread and the internal thread are in a matching state; with the continuous rotation of the bevel gear 4 and under the limitation of the anti-rotation limit pin 6, the movable plate 5 can make axial movement, thereby moving toward the direction of the bevel gear 3 or away from the bevel gear 3, so as to lock or unlock the static plate 4.

[0105] See also Figure 1-Figure 6 The working principle of the electronic mechanical parking mechanism of the present invention is:

[0106] When parking is required, the EMB drive motor 7 first builds pressure until the pressure meets the parking requirement. Next, the brushed motor 1 drives the worm helical gear 2 to rotate to drive the helical gear 3 to rotate. Since the movable plate 5 is limited in rotation by the stop pin 6, it can only move axially, and at the same time, the movable plate 5 and the helical gear 3 are driven by a thread. Therefore, under the continuous drive of the brushed motor 1, as the helical gear 3 continues to rotate, the helical gear 3 and the movable plate 5 are continuously squeezed toward the static plate 4 until the helical gear 3 and the movable plate 5 clamp both sides of the static plate 4 at the same time. Since the second locking surface 401 of the static plate 4 and the fourth locking surface 501 of the movable plate 5 are both provided with a ratchet structure, the ratchet structure is provided to replace the traditional knurling structure. When the ratchets on the second locking surface 401 of the static plate 4 and the fourth locking surface 501 of the movable plate 5 are embedded, friction locking can be achieved, thereby solving the potential risk of wear failure of the knurling pattern structure. Since the stator plate 4 and the main shaft of the EMB drive motor 7 are connected via the spline 8 to achieve torque transmission, the parking force can be maintained, thereby realizing the parking function.

[0107] In addition, in controlling the electronic mechanical parking mechanism of the present invention, the rotation angle of the brush motor 1 can be monitored in real time by an angle sensor, and then the axial movement distance of the moving plate 5 is converted and calculated to confirm whether the ratchet teeth on the second locking surface 401 in the static plate 4 and the fourth locking surface 501 in the moving plate 5 are completely engaged with each other; if it is detected that the rotation angle of the brush motor 1 is insufficient, the main shaft of the EMB drive motor 7 is driven to rotate in the opposite direction by an angle (i.e., the compensation angle) in a fixed compensation manner, and the brush motor 1 is driven to rotate at the same time, so as to achieve that the ratchet teeth on the second locking surface 401 in the static plate 4 and the fourth locking surface 501 in the moving plate 5 are completely engaged with each other.

[0108] When the parking brake needs to be released, the EMB drive motor 7 is first blocked according to the driving torque required for parking; then the brush motor 1 rotates in the opposite direction to drive the worm bevel gear 2 to drive the bevel gear 3 to rotate in the opposite direction, so that the moving plate 5 and the bevel gear 3 are away from the static plate 4, thereby realizing the parking brake release.

[0109] Example 2

[0110] See also Figure 7The electronic mechanical braking system of the present invention includes a housing, an EMB drive motor arranged on the housing, a reducer assembly, a motion switching mechanism and the electronic mechanical parking mechanism described in Example 1, wherein the reducer assembly is used to transmit the power of the EMB drive motor to the motion switching mechanism, and the motion switching mechanism refers to a device that can convert the power of linear motion and the power of rotational motion into each other, usually referring to a ball screw, a trapezoidal screw or a sliding screw, etc.; the motion switching mechanism is installed in the caliper, and is used to drive the caliper piston to perform linear motion to achieve braking or release the brake.

[0111] Example 3

[0112] See also Figure 8 The design method of the electronic mechanical parking mechanism of the present invention comprises the following steps:

[0113] Step S1: Calculate the clamping force required for parking and the parking brake torque required to be provided by the main shaft of the EMB drive motor according to the vehicle information;

[0114] In this embodiment, the calculation process of the parking brake torque that the main shaft of the EMB drive motor needs to provide is:

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

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

[0117]

[0118] Where, σ is the parking brake force safety factor, σ>1, generally 1.2~1.5;

[0119] Step S103: The required braking force F of the vehicle b and the friction coefficient μ1 of the brake disc, the piston thrust F output by the EMB actuator required for parking is calculated;

[0120]

[0121] When the EMB is parked, since the motion conversion mechanism does not have a self-locking function, it has a tendency to be reverse-driven, that is, the motion conversion mechanism has reverse motion; therefore, the motion conversion mechanism will reversely drive the main shaft of the EMB drive motor through the reducer with the torque;

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

[0123]

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

[0125] Step S105: The torque N required at the screw input end when maintaining the parking thrust s And the transmission ratio i1 of the EMB reducer assembly; calculate the torque N that the main shaft of the EMB drive motor needs to provide a ;

[0126]

[0127] Step S2: According to the parking brake torque required by the main shaft of the EMB drive motor, the ratchet parameters of the ratchet structure between the second locking surface of the static plate and the fourth locking surface of the dynamic plate are optimally designed; in this embodiment, the torque N required for parking is calculated. a After that, the ratchet teeth between the second locking surface and the fourth locking surface need to provide at least N a At the same time, since the movable plate is designed with a stop-rotation limit pin, the parking torque is transmitted from the stationary plate to the movable plate through the ratchet, and is finally maintained by the stop-rotation limit pin on the movable plate; therefore, the design steps of the parameters of the ratchet in the second locking surface of the stationary plate and the fourth locking surface of the movable plate are as follows:

[0128] Step S201: Calculate the friction torque N required between the first locking surface of the stator plate and the third locking surface of the bevel gear. h ;

[0129]

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

[0131] Step S202: The torque N required to be provided by the main shaft of the EMB driving motor aAnd the friction torque N between the first locking surface of the stator plate and the third locking surface of the bevel gear h , calculate the parking torque N required between the second locking surface of the static plate and the fourth locking surface of the dynamic plate j ;

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

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

[0134]

[0135] Step S204: According to the torque N that each ratchet needs to bear c , the radius R of the static disk and the radius r of the center hole of the static disk, where the radius r of the center hole of the static disk is determined by the main shaft of the EMB drive motor; calculate the shear force F borne by each ratchet c ;

[0136]

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

[0138]

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

[0140]

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

[0142] τ1≤Kτ allow ;

[0143] Where: τ allow It indicates the allowable shear strength of the materials of the moving plate and the static plate, K indicates the safety factor, and K is less than 1;

[0144] Step S208: Constructing a minimum static disk radius calculation model:

[0145]

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

[0147] Step S3: Design the parameters of the stop pin on the moving plate according to the parking brake torque required to be provided by the main shaft of the EMB drive motor.

[0148] In this embodiment, since the parking torque is ultimately maintained by the stop pin on the moving plate, the size and number of the stop pin need to be selected and designed according to the braking force required by the vehicle model; therefore, the steps for designing the parameters of the stop pin on the moving plate are as follows:

[0149] Step S301: The torque N required by the main shaft of the motor driven by the EMB a and the number of stop pins k, calculate the torque N required for each stop pin on the moving plate k ;

[0150]

[0151] Step S302: The torque N required to be provided by each stop pin on the moving plate k And the distance D from the center axis of each stop pin to the center axis of the moving plate, calculate the shear force F on each stop pin on the moving plate k ;

[0152]

[0153] Step S303: According to the shear force F exerted on each stop pin on the moving plate k and the cross-sectional area A of the stop pin, calculate the shear strength τ of the stop pin k ;

[0154]

[0155] Where: d represents the diameter of the stop pin;

[0156] Step S304: In order to ensure that the stop pin meets the shearing requirements of the parking torque, select a pin diameter that meets the standard (such as the cylindrical pin specifications specified in GB / T 118 or ISO standards); the shear strength τ of each stop pin k Imposing safety constraints, namely:

[0157]

[0158] Where: τ allowIndicates the allowable shear strength of the material, K indicates the safety factor, and K < 1;

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

[0160]

[0161] Under the premise of meeting the safety constraints, the constructed minimum diameter model of the stop pin is solved to calculate the minimum diameter d of the stop pin.

[0162] Example 4

[0163] See also Fig. 9 The control method of the electronic mechanical parking mechanism of the present invention comprises the following steps:

[0164] Step 1: When the EMB builds up pressure to park, the EMB drives the motor to drive the spindle to build up a preliminary parking pressure F2 that is greater than the actual required parking pressure F1;

[0165] F2 = x1F1;

[0166] In the formula: x1 indicates that the parking force that the EMB drive motor needs to initially establish is a multiple of the theoretically calculated parking force, x1>1, and is generally 1.2-1.5; F1 indicates the theoretically calculated parking force, and this value is selected by calculation based on the specific vehicle model;

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

[0168] Step 3: Detect the rotation angle of the brushed motor by using an angle sensor installed on the brushed motor to calculate the axial movement stroke of the static plate, and then determine whether the ratchet teeth on the static plate and the ratchet teeth on the dynamic plate are completely embedded;

[0169] The required rotation angle θ of the helical gear is calculated based on the moving stroke of the movable plate when the ratchet teeth of the second locking surface and the fourth locking surface are fully engaged. hg :

[0170]

[0171] Where: x2 represents the distance the moving plate moves axially when stable parking is achieved, that is, when the ratchet teeth on the static plate and the ratchet teeth on the moving plate are fully embedded; 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, the target rotation angle θ of the motor shaft of the brushed motor required to rotate when the ratchet teeth in the second locking surface and the fourth locking surface are fully engaged is calculated according to the transmission ratio of the staggered helical gears. a :

[0173] θ a =i2θ hg ;

[0174] Where: θ a represents the target rotation angle of the brushed motor, and i2 represents the transmission ratio of the staggered helical gears;

[0175] If the angle sensor detects the actual rotation angle θ of the brushed motor t Smaller than the target rotation angle θ of the brushless motor a , it indicates that the travel of the static disk is insufficient, and the ratchet teeth between the second locking surface and the fourth locking surface are not completely embedded, that is, they cannot meet the use requirements. At this time, the EMB drive motor drives its main shaft to the pressure relief direction to relieve pressure, and rotates and adjusts at an angle of 1 degree to 2 degrees at a time. At the same time, the brush motor continuously builds pressure until θ t =θ a , so that the ratchet teeth between the second locking surface and the fourth locking surface are completely embedded;

[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 , it indicates that the ratchet teeth between the second locking surface and the fourth locking surface have been completely embedded, meeting the parking requirements.

[0177] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An electronic mechanical parking mechanism, characterized in that: It includes a stator plate arranged on the main shaft of the EMB drive motor and a double-sided locking mechanism for locking the stator plate, wherein: The static disk is fixedly connected to the main shaft of the EMB drive motor; The double-sided locking mechanism includes a moving plate and a linear driving mechanism for driving the moving plate to perform linear motion, wherein the linear driving mechanism includes a helical gear and a rotary driving mechanism for driving the helical gear to rotate; the helical gear and the moving plate are respectively located on both sides of the static plate, and the three are coaxially arranged; the moving plate is mounted on the housing through a sliding connection structure; the sliding connection structure is used to enable the moving plate to move along the axial direction of the main shaft of the EMB drive motor; the helical gear and the moving plate are connected through a threaded transmission structure; A friction structure is provided between the helical gear and the static plate, and a ratchet structure is provided between the dynamic plate and the static plate; The rotary drive mechanism comprises a brushed motor and a worm bevel gear, wherein the worm bevel gear is mounted on the main shaft of the brushed motor, and the worm bevel gear is meshed with the bevel gear in a vertically staggered arrangement.

2. The electromechanical parking mechanism according to claim 1, characterized in that: A first locking surface and a second locking surface are respectively provided on both sides of the stationary plate, wherein the bevel 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 movable plate is provided with a fourth locking surface at a position corresponding to the second locking surface, and the ratchet structure includes ratchets respectively provided on the second locking surface and the fourth locking surface.

3. The electromechanical parking mechanism according to claim 1, characterized in that: A spline is provided between the stator and the main shaft of the EMB drive motor. The spline is fixedly mounted on the main shaft of the EMB drive motor; and the stator is fixedly mounted on the spline.

4. The electromechanical parking mechanism according to claim 1, characterized in that: The sliding connection structure includes a plurality of groups of anti-rotation limit pins arranged on the movable disk, and the plurality of groups of anti-rotation limit pins are evenly arranged along the circumferential direction of the movable disk; and the outer shell is provided with a plurality of groups of limit holes cooperating with the anti-rotation limit pins.

5. The electromechanical parking mechanism according to claim 2, characterized in that: The threaded transmission structure includes an internal thread arranged in the inner cavity of the bevel gear, and the outer diameter of the internal thread is larger than the outer diameter of the static plate; an external thread matching the internal thread is arranged on the outer circumferential surface of the dynamic plate; in the initial state, the external thread and the internal thread are in a matching state.

6. A design method for an electromechanical parking mechanism according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1: Calculate the clamping force required for parking and the parking brake torque required to be provided by the main shaft of the EMB drive motor according to the vehicle information; Step S2: optimally designing the ratchet parameters of the ratchet structure between the second locking surface of the static plate and the fourth locking surface of the dynamic plate according to the parking brake torque required to be provided by the main shaft of the EMB drive motor; Step S3: Design the parameters of the stop pin on the moving plate according to the parking brake torque required to be provided by the main shaft of the EMB drive motor.

7. The design method of the electronic mechanical parking mechanism according to claim 6, characterized in that: In step S1, the calculation process of the parking brake torque required to be provided by the main shaft of the EMB drive motor is: Step S101: Calculate the parking braking torque N required for a single wheel side of the vehicle based on vehicle information; Step S102: Calculate the braking force F required for a single wheel side of the vehicle during parking by using the parking braking force torque N required for a single wheel side of the vehicle and the wheel braking radius b. b : Where, σ is the parking brake force safety factor, σ>1, and the value range is [1.2, 1.5]; Step S103: The required braking force F of the vehicle b and the friction coefficient μ1 of the brake disc, the piston thrust F output by the EMB actuator required for parking is calculated; Step S104: Calculate the torque N required to be applied to the screw end to achieve the target parking thrust force by using the piston thrust F of the EMB during parking and the screw lead L1. s ; Where: η1 represents the efficiency of the ball screw assembly, η2 represents the efficiency of the EMB clamp assembly; Step S105: The torque N required at the screw input end when maintaining the parking thrust s and the transmission ratio i1 of the EMB reducer assembly; Calculate the torque N that the spindle of the EMB drive motor needs to provide a ; 8. The design method of the electronic mechanical parking mechanism according to claim 7, characterized in that: In step S2, the design steps of the ratchet parameters of the ratchet structure in the second locking surface of the static plate and the fourth locking surface of the dynamic plate are as follows: Step S201: Calculate the friction torque N required between the first locking surface of the stator plate and the third locking surface of the bevel gear. h ; Where: N d is the rated torque of the brushed motor; μ2 is the friction coefficient between the first locking surface of the stator and the third locking surface of the helical gear; i2 is the transmission ratio between the staggered helical gears; ξ1 is the transmission efficiency between the staggered helical gears; r a is the thread radius of the thread transmission structure between the helical gear and the moving plate; η3 is the transmission efficiency of the thread transmission structure between the helical gear and the moving plate; Step S202: The torque N required to be provided by the main shaft of the EMB driving motor a And the friction torque N between the first locking surface of the stator plate and the third locking surface of the bevel gear h , calculate the parking torque N required between the second locking surface of the static plate and the fourth locking surface of the dynamic plate j ; N j =N a -N h ; Step S203: According to the parking torque N j And the centripetal angle θ corresponding to a single ratchet, calculate the number of ratchets C, and then calculate the torque N that each ratchet needs to bear c ; Step S204: According to the torque N that each ratchet needs to bear c , the radius R of the static disk and the radius r of the center hole of the static disk, where the radius r of the center hole of the static disk is determined by the main shaft of the EMB drive motor; calculate the shear force F borne by each ratchet c ; Step S205: Calculate the radial cross-sectional area S of each ratchet tooth by using the radius R of the stator disk, the radius r of the center hole of the stator disk and the number C of ratchet teeth; Step S206: Determine the radial cross-sectional area S of each ratchet tooth, and calculate the shear force F borne by each ratchet tooth. c , calculate the shear strength τ1 borne by each ratchet; Step S207: Apply a safety constraint to the shear strength τ1 borne by each ratchet, namely: τ1≤Kτ allow ; Where: τ allow It indicates the allowable shear strength of the materials of the moving plate and the static plate, K indicates the safety factor, and K is less than 1; Step S208: Constructing a minimum static disk radius calculation model: Under the premise of satisfying the safety constraints, the constructed minimum static disk radius calculation model is solved to obtain the minimum static disk radius R.

9. The design method of the electronic mechanical parking mechanism according to claim 7, characterized in that: In step S3, the steps for designing the parameters of the anti-rotation limit pin on the moving plate are: Step S301: The torque N required by the main shaft of the motor driven by the EMB a and the number of stop pins k, calculate the torque N required for each stop pin on the moving plate k ; Step S302: The torque N required to be provided by each stop pin on the moving plate k And the distance D from the center axis of each stop pin to the center axis of the moving plate, calculate the shear force F on each stop pin on the moving plate k ; Step S303: According to the shear force F exerted on each stop pin on the moving plate k and the cross-sectional area A of the stop pin, calculate the shear strength τ of the stop pin k ; Where: d represents the diameter of the stop pin; Step S304: The shear strength τ of each stop pin k Imposing safety constraints, namely: t k ≤Kτ allow ; Where: τ allow Indicates the allowable shear strength of the material of the stop pin, K indicates the safety factor, and K < 1; Step S305: constructing a minimum diameter model of the anti-rotation limit pin shaft; Under the premise of meeting the safety constraints, the constructed minimum diameter model of the stop pin is solved to calculate the minimum diameter d of the stop pin.

10. A control method for the electronic mechanical parking mechanism according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: When the EMB builds up pressure to park, the EMB drives the motor to drive the spindle to build up a preliminary parking pressure F2 that is greater than the actual required parking pressure F1; F2 = x1F1; Where: x1 indicates that the parking force that the EMB drive motor needs to initially establish is a multiple of the theoretically calculated parking force, F1 indicates the theoretically calculated parking force, and this value is selected by the specific vehicle model; x1>1, and its value range is 1.2-1.5;, Step 2: The brushed motor drives the worm helical gear to rotate, thereby driving the helical gear to rotate. While the helical gear rotates, the threaded transmission structure drives the moving plate to move axially, thereby clamping the static plate between the helical gear and the moving plate; Step 3: Detect the rotation angle of the brushed motor by using the angle sensor installed on the brushed motor to calculate the axial movement stroke of the moving plate, and then determine whether the ratchet teeth on the stationary plate and the ratchet teeth on the moving plate are completely embedded; The required rotation angle θ of the helical gear is calculated based on the moving stroke of the movable plate when the ratchet teeth of the second locking surface and the fourth locking surface are fully engaged. hg : Where: x2 represents the distance the moving plate moves axially when stable parking is achieved, that is, when the ratchet teeth on the static plate and the ratchet teeth on the moving plate are fully embedded; 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, the target rotation angle θ of the motor shaft of the brushed motor required to rotate when the ratchet teeth in the second locking surface and the fourth locking surface are fully engaged is calculated according to the transmission ratio of the staggered helical gears. a : i a =i2θ hg ; Where: θ a represents the target rotation angle of the brushed motor, and i2 represents the transmission ratio of the staggered helical gears; If the angle sensor detects the actual rotation angle θ of the brushed motor t Smaller than the target rotation angle θ of the brushless motor a , it indicates that the travel of the static disk is insufficient, and the ratchet teeth between the second locking surface and the fourth locking surface are not completely embedded, that is, they cannot meet the use requirements. At this time, the EMB drive motor drives its main shaft to the pressure relief direction to relieve pressure, and rotates and adjusts at an angle of 1 degree to 2 degrees at a time. At the same time, the brush motor continuously builds pressure until θ t =θ a , so that the ratchet teeth between the second locking surface and the fourth locking surface are completely embedded; 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 , it indicates that the ratchet teeth between the second locking surface and the fourth locking surface have been completely embedded, meeting the parking requirements.

Images