Drive disengagement mechanism and automobile

Abstract

The present invention provides a drive disengagement mechanism and a vehicle. The drive disengagement mechanism is used in a pure electric four-wheel drive vehicle and includes: a shift drum having a camshaft, wherein a cam groove is formed on the surface of the camshaft for accommodating a positioning pin of a shift fork, the cam groove including a disengagement stroke groove and a return stroke groove; the disengagement stroke groove is configured so that, when the drive is disengaged or engaged, the positioning pin drives the driven pin of the shift fork to move the gear sleeve of the synchronizer assembly left and right, thereby outputting or cutting off power; the return stroke groove is configured so that, after the drive is engaged, a gap exists between the driven pin and both convex edges of the gear sleeve. The drive disengagement mechanism and vehicle provided by the present invention can reduce collision between the shift fork and the gear sleeve, avoid NVH friction noise, reduce wear between the two, and increase component life.

Description

Technical Field

[0001] The present invention relates to the technical field of automobiles, in particular to a drive disengagement mechanism and an automobile. Background Art

[0002] A cam groove is a curved profile or groove on the surface of a cam. A cam drive converts rotary motion into linear motion by controlling the cam groove's curve. This motion is transmitted to a roller moving close to its edge or to a needle bar moving freely on the groove surface, or it receives force from such rollers and needle bars. A cam mechanism generally consists of a main body, a stopper, and a connecting link. While the main body rotates at a constant angular velocity, the cam groove curve on the main body can be adjusted to cause the connecting link to move linearly at the desired speed along the stopper's groove. Summary of the Invention

[0003] The purpose of the present invention is to provide a drive disengagement mechanism and a vehicle to reduce the BLDC starting load, reduce the collision between the shift fork and the camshaft groove, and avoid friction between the shift fork and the tooth groove of the gear sleeve after engagement, thereby improving NVH performance and increasing component life.

[0004] The present invention first provides a drive disengagement mechanism for a pure electric four-wheel drive vehicle, comprising: a shift drum having a camshaft, a cam groove for accommodating a positioning pin of a shift fork being opened on the surface of the camshaft, the cam groove comprising a disengagement stroke groove and a return stroke groove; the disengagement stroke groove is shaped so that, when the drive is disengaged or engaged, the positioning pin drives the driven pin of the shift fork to move the gear sleeve of the synchronizer assembly left and right, thereby outputting or cutting off power; the return stroke groove is shaped so that, after the drive is engaged, there is a gap between the driven pin and the two convex edges of the gear sleeve.

[0005] Furthermore, the drive disengagement mechanism further includes a shift fork, the shift fork having the positioning pin and the driven pin, the positioning pin is connected to the shift drum, and the driven pin is detachably connected to the synchronizer ring on the gear sleeve of the synchronizer assembly.

[0006] Furthermore, the cam groove also includes a first idle stroke groove connected to the disengagement stroke groove, and the first idle stroke groove is formed as follows: when driving disengagement and power-on self-learning, the driving current of the disengagement motor is reduced; when driving from engagement to disengagement, the operating speed of the disengagement motor is slowed down; when driving engagement, the operating speed of the disengagement motor is adjusted according to the speed difference at both ends of the synchronizer assembly; the disengagement motor provides power for the driving disengagement mechanism.

[0007] Furthermore, the cam groove also includes a second idle stroke groove opened between the disengagement stroke groove and the return stroke groove, and the second idle stroke groove is formed as follows: before the drive engagement is completed, the operating speed of the disengagement motor is slowed down; when the drive is disengaged, the operating speed of the disengagement motor is adjusted according to the torque difference at both ends of the synchronizer; the disengagement motor provides power for the drive disengagement mechanism.

[0008] Furthermore, the drive disengagement mechanism also includes a disengagement motor, which obtains a torque demand signal from the vehicle controller and causes the synchronizer assembly to output or cut off power according to the torque demand.

[0009] Furthermore, the driving disengagement mechanism also includes a deceleration mechanism, which includes a multi-stage reducer, the input end of the multi-stage reducer is connected to the disengagement motor, and the output end is connected to the shift drum; the multi-stage reducer reduces the speed output by the disengagement motor, and amplifies the torque output by the disengagement motor and transmits it to the shift drum.

[0010] Furthermore, the multi-stage reducer includes a first-stage reducer and a second-stage reducer connected in series, the input end of the first-stage reducer is connected to the disengagement motor, and the output end of the second-stage reducer is connected to the shift drum.

[0011] Furthermore, a position sensor is provided on the shift fork, and the position sensor monitors the left and right movement of the shift fork through a permanent magnet, and feeds back the shift fork position information to the vehicle controller.

[0012] Furthermore, the vehicle controller is also connected to the disengagement motor, and the vehicle controller determines the actual position of the driving disengagement mechanism based on the disengagement motor angle information and the fork position information.

[0013] The present invention also provides a pure electric four-wheel drive vehicle, which has any one of the above-mentioned drive disengagement mechanisms.

[0014] The drive disengagement mechanism and automobile provided by the present invention can reduce the BLDC starting load, reduce the collision between the shift fork and the camshaft groove, avoid friction between the shift fork and the tooth groove of the gear sleeve after engagement, avoid NVH friction sound, reduce wear between the two, and thus avoid drivability problems of the entire vehicle when engaged. The present invention can improve the NVH performance of the automobile and increase the life of components. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of a disengagement mechanism according to an embodiment of the present invention.

[0016] Figure 2 It is a schematic diagram of the working principle of the disengagement mechanism of an embodiment of the present invention.

[0017] Figure 3It is a schematic diagram of the working process of the shift fork and the gear sleeve of the disengagement mechanism according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0019] The terms "first," "second," "third," and "fourth" in the specification and claims of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "installed," "connected," "connected," and "fixed" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or mutual communication; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0020] First embodiment

[0021] This embodiment provides a drive disengagement mechanism for a pure electric four-wheel drive vehicle, including a shift drum 62. Figures 1 to 3 The shift drum 62 has a camshaft 68 with a cam groove 66 formed on its surface. The cam groove 66 is used to accommodate the positioning pin 642 of the shift fork 64. The cam groove 66 includes a disengagement stroke groove 662 and a return stroke groove 664. The disengagement stroke groove 662 is configured so that, when the drive is disengaged or engaged, the positioning pin 642 drives the driven pin 644 of the shift fork 64 to move the gear sleeve 54 of the synchronizer assembly 50 left and right, thereby outputting or cutting off power. The return stroke groove 664 is configured so that, after the drive is engaged, a return clearance G exists between the driven pin 644 and both the raised edge a 542 and the raised edge b 544 of the gear sleeve 54. That is, the return stroke groove is set to produce the following effects: (1) after the disengagement mechanism is engaged, there is a gap between the shift fork and the a and b surfaces of the gear sleeve to avoid wear and NVH friction noise; (2) during the locking stage after the disengagement mechanism is engaged, the vibration impact during the vehicle driving process is avoided, which causes the synchronizer gear sleeve to vibrate toward the gear sleeve a side when engaged, causing the disengagement mechanism to disengage.

[0022] This embodiment notes that when a pure electric four-wheel drive vehicle utilizes a disengageable mechanism for front or rear drive, the shift drum camshaft groove in the disengagement mechanism converts rotational motion into axial linear motion of the shift fork, making groove design crucial. Based on this, this embodiment provides a return zone (i.e., the aforementioned return travel groove) after the camshaft groove is engaged. This prevents the shift fork and sleeve from continuously contacting and rubbing against each other during sleeve rotation after the disengagement mechanism is engaged, thereby preventing NVH friction noise, reducing wear between the two, and maintaining the disengagement mechanism locked.

[0023] See also Figure 2 Specifically, the cam groove 66 includes a first idle stroke groove 666 connected to the disengagement stroke groove 662. The first idle stroke groove 666 is formed to: reduce the driving current of the disengagement motor when driving disengagement and power-on self-learning; slow down the operating speed of the disengagement motor during the driving process from engagement to disengagement; and adjust the operating speed of the disengagement motor according to the speed difference between the two ends of the synchronizer assembly 50 when driving engagement. The disengagement motor provides power for driving the disengagement mechanism. In other words, the first idle stroke groove 666 is configured to produce the following effects: (1) when the disengagement mechanism is in the disengagement position when the vehicle is powered off and the vehicle is in the power-on self-learning state, avoid excessive starting current of the BLDC motor; (2) when the positioning pin is identified to enter the idle stroke, the operating speed of the disengagement motor can be slowed down to avoid excessive speed causing a large impact, affecting the life of the disengagement mechanism and the NVH performance of the vehicle; (3) when engaged, the disengagement motor can be allowed to adjust the speed when the positioning pin is in the first idle stroke.

[0024] Specifically, see Figure 2 The cam groove 66 also includes a second idle stroke groove 668 defined between the disengagement stroke groove 662 and the return stroke groove 664. The second idle stroke groove 668 is configured to slow down the disengagement motor before the drive engagement is complete and to adjust the disengagement motor's speed based on the torque difference across the synchronizer during drive disengagement. The disengagement motor provides power for driving the disengagement mechanism. In other words, the second idle stroke groove 668 primarily functions as a speed regulation zone: slowing down the disengagement motor's speed near the end of the disengagement mechanism engagement and adjusting the disengagement motor's speed based on the torque difference across the synchronizer during disengagement to avoid torque shock caused by disengagement when the torque difference is large.

[0025] Second embodiment

[0026] This embodiment also provides a drive disengagement mechanism for a pure electric four-wheel drive vehicle. In addition to the shift drum 62 , it also includes a shift fork 64 used in conjunction with it, a disengagement motor, a vehicle controller, and a reduction mechanism.

[0027] Specifically, the drive disengagement mechanism may further include the shift fork 64 , which has a positioning pin 642 and a driven pin 644 . The positioning pin 642 is connected to the shift drum 62 , and the driven pin 644 is detachably connected to the synchronizer ring on the gear sleeve 54 of the synchronizer assembly 50 .

[0028] Specifically, the drive disengagement mechanism may further include a disengagement motor, which obtains a torque demand signal from the vehicle controller and enables the synchronizer assembly 50 to output or cut off power according to the torque demand.

[0029] Specifically, the drive disengagement mechanism may further include a reduction mechanism, which includes a multi-stage reducer, the input end of the multi-stage reducer is connected to the disengagement motor, and the output end is connected to the shift drum 62; the multi-stage reducer reduces the speed output by the disengagement motor and amplifies the torque output by the disengagement motor before transmitting it to the shift drum 62. The multi-stage reducer preferably has a two-stage reducer, such as Figure 1 As shown, the multi-stage reducer may include a first-stage reducer 42 and a second-stage reducer 44 connected in series. The input end of the first-stage reducer 42 is connected to the disconnect motor, and the output end of the second-stage reducer 44 is connected to the shift drum 62 .

[0030] Specifically, the shift fork 64 can be equipped with a position sensor that monitors the left and right movement of the shift fork 64 via a permanent magnet and feeds the fork position information back to the vehicle controller. The vehicle controller can also be connected to the disengagement motor. In this case, the vehicle controller verifies the actual position of the disengagement mechanism based on the disengagement motor's rotation angle information and the shift fork's position information. At this time, the effects produced by the first idle stroke groove 666 include: (1) when the disengagement mechanism is in the disengagement position when the vehicle is powered off, and the vehicle is in the power-on self-learning state, since the resistance encountered by the driving mechanism in the idle stroke is small, the disengagement motor can be a BLDC motor, which only needs to drive the camshaft to rotate, thereby avoiding excessive starting current of the BLDC motor; (2) from the engagement to the disengagement process, the controller can identify that the positioning pin enters the idle stroke based on the BLDC rotation angle position and the shift fork position feedback from the position sensor, thereby slowing down the running speed of the disengagement motor to avoid excessive speed causing a large impact, affecting the life of the disengagement mechanism and the NVH performance of the vehicle; (3) when engaged, the disengagement motor can adjust the speed when the positioning pin is in the first idle stroke: when the speed difference between the two ends of the synchronizer is small, the speed is increased; when the speed difference between the two ends of the synchronizer is large, the speed is reduced, and the large motor is waited for to adjust the speed to reduce the speed difference between the two ends of the synchronizer.

[0031] Third embodiment

[0032] This embodiment provides a pure electric four-wheel drive vehicle, which has any of the above-mentioned drive disengagement mechanisms. Figure 2 and Figure 3The engagement and disengagement working principles of a pure electric four-wheel drive vehicle using the above-mentioned drive disengagement mechanism are as follows:

[0033] Combination principle:

[0034] First, when the follower pin is in the disengaged position S1, the camshaft 68 rotates forward, and the positioning pin remains stationary in the first idle stroke;

[0035] Then, the camshaft 68 continues to rotate forward, enters the engagement stroke, and reaches the engagement position S2. The positioning pin 642 is pushed to the right by the wall surface 663 of the cam groove a, so that the shift fork 64 acts on the edge 544 of the gear sleeve b to push the gear sleeve 54 to the right, and the synchronizer assembly 50 gradually changes from disengagement to engagement.

[0036] Then, the camshaft 68 continues to rotate forward and enters the second idle stroke, and the positioning pin 642 remains stationary;

[0037] Finally, the camshaft 68 continues to rotate forward, enters the return stroke, and reaches the return position S3. The cam groove b wall 665 pushes the positioning pin 642 slightly to the left until it reaches the dead center position, thereby disengaging the driven pin 644 from the gear sleeve a side 542 and the gear sleeve b side 544. The synchronizer assembly 50 is now engaged.

[0038] Disengagement principle:

[0039] First, when the follower pin 644 is in the engaged position, the cam shaft 68 rotates in reverse, and during the return stroke, the cam groove a wall surface 663 pushes the positioning pin 642 to move slightly to the right;

[0040] Then, the camshaft 68 continues to reverse and enters the second idle stroke, and the positioning pin 642 remains stationary;

[0041] Then, the camshaft 68 continues to reverse and enters the disengagement stroke. The wall surface 665 of the cam groove b pushes the positioning pin 642 to move leftward. After the shift fork 64 is pushed to the edge 542 of the gear sleeve a, it pushes the gear sleeve 54 to move leftward. The synchronizer assembly 50 gradually moves from engagement to disengagement.

[0042] Finally, the camshaft 68 continues to reverse and enters the first idle stroke, and the positioning pin 642 remains stationary until the dead center position.

[0043] In the above, the BLDC motor drives the camshaft 68 in forward and reverse rotation, thereby achieving the engagement and disengagement of the synchronizer. Taking the above disengagement mechanism as a front-wheel drive disengagement mechanism as an example, the front-wheel drive disengagement mechanism can disengage the front-wheel drive in a pure electric four-wheel drive vehicle, so that the front-wheel drive motor is not reverse-drag and the rear-wheel drive is driven independently, avoiding the economic and drivability issues caused by reverse drag of the front-wheel drive motor rotor and zero-torque control.

[0044] The camshaft groove is designed with idle strokes at both ends, which has the following functions: 1) Avoiding large collisions between the groove and the follower pin: When the disengagement mechanism is completed and enters the idle stroke, the BLDC motor speed can be slowed down to reduce the cam speed, avoiding large collision forces between the camshaft groove and the follower pin when rotating to the dead center, avoiding NVH collision sounds, and reducing collision wear between the groove and the follower pin; 2) Preparing for the engagement action: When the disengagement mechanism receives the engagement command and runs during the idle stroke, the drive motor can adjust the speed during this period. In this way, when the speed difference between the drive shaft and the half shaft is within the engagement range, the BLDC can quickly adjust the speed to allow the disengagement mechanism to engage quickly, avoiding drivability problems caused by slow engagement.

[0045] The camshaft groove is provided with a return zone after engagement. Its function is to prevent the shift fork and the gear sleeve from being in constant contact and friction when the gear sleeve rotates after the disengagement mechanism is engaged, thereby avoiding NVH friction sound and reducing wear between the two.

[0046] In summary, the present invention notes that the disengagement and engagement of the disengagement structure requires the axial movement of the shift fork to push the gear sleeve, thereby achieving the disengagement and engagement of the synchronizer assembly. The front-drive disengageable mechanism controller controls the rotation of the BLDC, which drives the rotation of the shift drum. Converting rotation into axial movement requires a rationally designed groove on the shift drum camshaft. Improper groove design can result in large BLDC starting torque, making control difficult, and easily causing collisions between the groove and the driven pin, leading to NVH and driving issues, while also affecting the life of the shift fork, driven pin, and groove. Therefore, the grooves designed in the present invention include a first idle travel groove, a second idle travel groove, an engagement / disengagement travel groove, and a return travel groove.

[0047] The first idle stroke groove can slow down the BLDC motor speed when the vehicle enters the idle stroke to reduce the cam speed, avoid a large collision force between the camshaft groove and the follower pin when rotating to the dead point, avoid NVH collision sound, and reduce the collision wear between the groove and the follower pin. The second idle stroke groove can adjust the execution speed of the engagement during the synchronizer engagement process, so that the engagement process reaches the optimal state and avoids drivability problems of the entire vehicle during engagement. The return stroke groove can avoid the continuous contact and friction between the shift fork and the gear sleeve when the gear sleeve rotates after the disengagement mechanism is engaged, avoid NVH friction sound, and reduce wear between the two. The present invention solves the problems of large BLDC starting torque, large collision force between the follower pin and the groove, collision sound when the disengagement mechanism is engaged or at the end of disengagement, avoids drivability problems during the engagement process, and solves direct friction between the shift fork and the gear sleeve after engagement through reasonable control.

[0048] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A drive disengagement mechanism for a pure electric four-wheel drive vehicle, characterized in that: include: A shift drum (62) has a camshaft (68), a cam groove (66) for accommodating a positioning pin (642) of a shift fork (64) is formed on a surface of the camshaft (68), and the cam groove (66) includes a disengagement stroke groove (662) and a return stroke groove (664); The disengagement stroke groove (662) is formed so that when the drive is disengaged or engaged, the positioning pin (642) drives the driven pin (644) of the shift fork (64) to move the gear sleeve (54) of the synchronizer assembly (50) left and right, thereby outputting or cutting off power; The return stroke groove (664) is formed so that, after driving engagement, a gap exists between the driven pin (644) and the two convex edges of the gear sleeve (54); The cam groove (66) further includes a first idle stroke groove (666) communicating with the disengagement stroke groove (662); The cam groove (66) further includes a second idle stroke groove (668) formed between the disengagement stroke groove (662) and the return stroke groove (664); The invention also includes a shift fork (64), wherein the shift fork (64) has the positioning pin (642) and the driven pin (644), wherein the positioning pin (642) is connected to the shift drum (62), and the driven pin (644) is detachably connected to the synchronizer ring on the gear sleeve (54) of the synchronizer assembly (50).

2. The drive disengagement mechanism according to claim 1, wherein: The first idle travel groove (666) is formed as follows: When the drive is disconnected or self-learning is performed after power on, the drive current of the disconnected motor is reduced; When the drive is from engagement to disengagement, slow down the speed of the disengagement motor; When the drive is engaged, the operating speed of the disengaging motor is adjusted according to the speed difference between the two ends of the synchronizer assembly (50); The disengagement motor provides power to the drive disengagement mechanism.

3. The drive disengagement mechanism according to claim 1, wherein: The second idle stroke groove (668) is formed as follows: Before the drive engagement ends, slow down the running speed of the disengaging motor; When the drive is disengaged, the operating speed of the disengaging motor is adjusted according to the torque difference at both ends of the synchronizer; The disengagement motor provides power to the drive disengagement mechanism.

4. The drive disengagement mechanism according to claim 2 or 3, characterized in that: It also includes a disengagement motor, which obtains a torque demand signal from a vehicle controller and causes the synchronizer assembly (50) to output or cut off power according to the torque demand.

5. The drive disengagement mechanism according to claim 4, wherein: It also includes a reduction mechanism, which includes a multi-stage reducer, the input end of the multi-stage reducer is connected to the disengagement motor, and the output end is connected to the shift drum (62); the multi-stage reducer reduces the speed output by the disengagement motor, and amplifies the torque output by the disengagement motor and transmits it to the shift drum (62).

6. The drive disengagement mechanism according to claim 5, wherein: The multi-stage reducer comprises a first-stage reducer (42) and a second-stage reducer (44) connected in series, the input end of the first-stage reducer (42) is connected to the disengagement motor, and the output end of the second-stage reducer (44) is connected to the shift drum (62).

7. The drive disengagement mechanism according to claim 4, wherein: A position sensor is provided on the shift fork (64), and the position sensor monitors the left and right movement of the shift fork (64) through a permanent magnet, and feeds back the shift fork position information to the vehicle controller.

8. The drive disengagement mechanism according to claim 7, wherein: The vehicle controller is also connected to the disengagement motor, and the vehicle controller determines the actual position of the driving disengagement mechanism according to the disengagement motor rotation angle information and the fork position information.

9. A pure electric four-wheel drive vehicle, characterized in that: The pure electric four-wheel drive vehicle has the drive disengagement mechanism according to any one of claims 1 to 8.

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