Axle suspension assembly detection bench

Abstract

The invention relates to the technical field of suspension detection, and discloses an axle suspension assembly detection platform, which comprises a lower frame, an upper frame, a suspension assembly main body, a boss and a connecting beam, a detection unit is arranged between the connecting beams and the suspension assembly body, dynamic and static balance detection can be conducted on the suspension assembly body through the detection unit so as to obtain dynamic balance detection data of the air spring, the detection unit comprises detection arms arranged below the connecting beams, and clamps are arranged at the ends, away from the connecting beams, of the detection arms. And the clamp is used for clamping and fixing the exterior of the suspension, so that the detection arm can apply pressure to the suspension conveniently, and dynamic balance detection is performed on the air spring. According to the invention, by changing the detection angle of the suspension assembly main body, multi-angle dynamic balance detection of the suspension assembly main body is realized, so that the detection arm applies pressure from different angles to obtain dynamic balance data of the suspension assembly main body.

Description

Technical Field

[0001] The present invention relates to the technical field of suspension detection, and more specifically, it relates to an axle suspension assembly detection bench. Background Art

[0002] The axle and the air suspension assembly integrated with the axle are key components for the driving of electric vehicles. Their quality and performance directly affect the safety performance of the vehicle. When the axle operates at high speed and under high load, fatigue cracks are likely to occur. When the axle is equipped with an air suspension assembly, under different loads, the lateral force of its airbag can cause deformation, and the air suspension assembly is prone to twisting, resulting in damage to the airbag. Therefore, it is required that the axle and its loaded air suspension assembly must pass performance tests before leaving the factory to ensure the safety of electric vehicle use. The detection bench for the axle suspension assembly of electric vehicles is a professional detection device developed specifically for the axle suspension system of electric vehicles, which can accurately detect various performance indicators of the axle suspension assembly, such as the stiffness of the suspension system, shock absorption effect, load-bearing capacity, etc., to comprehensively evaluate the working performance of the axle suspension assembly. Among them, as an important part of the vehicle chassis, the performance of the axle suspension system directly affects the driving stability, handling performance and riding comfort of electric vehicles. The dynamic balance and static balance states of the axle suspension assembly have a significant impact on the vibration characteristics and noise level of the whole vehicle.

[0003] In the dynamic balance test of the suspension assembly, it is necessary to consider the complex force conditions of the suspension system during actual use. In reality, the force borne by the suspension assembly is not only vertically downward, but the combined action from multiple directions. These forces may include the mutual influence in the lateral, longitudinal and vertical directions. Therefore, the traditional static test method cannot fully reveal the performance of the suspension assembly under real working conditions, and at the same time, it cannot effectively simulate the various force changes experienced by the suspension system during driving, reducing the accuracy of the test. Summary of the Invention

[0004] The present invention provides an axle suspension assembly detection bench to solve the technical problems in the related art that the force borne by the suspension assembly is not only vertically downward, but the combined action from multiple directions, the traditional static test method cannot fully reveal the performance of the suspension assembly under real working conditions, and at the same time, it cannot effectively simulate the various force changes experienced by the suspension system during driving, reducing the accuracy of the test.

[0005] The present invention provides an axle suspension assembly detection bench, which includes a lower frame, an upper frame, a suspension assembly main body, a convex platform and a connecting beam. The suspension assembly main body is placed on the convex platform. The connecting beams are symmetrically arranged inside the lower frame. The suspension assembly main body includes a suspension, and connecting frames are symmetrically arranged on the suspension. An air spring is provided between the suspension and the connecting frame. A detection unit is provided between the connecting beam and the suspension assembly main body to perform static and dynamic balance detection on the suspension assembly main body through the detection unit, so as to obtain dynamic balance detection data of the air spring. The detection unit includes a detection arm provided below each connecting beam, and a clamp is provided at the end of the detection arm far from the connecting beam. A universal joint is provided between the detection arm and the clamp. The clamp is used to clamp and fix the outside of the suspension, so as to facilitate the detection arm to apply pressure to the suspension and perform dynamic balance detection on the air spring.

[0006] As a further optimized solution of the present invention, an adjustment plate is installed on the connecting beam, and an adjustment groove is opened on the adjustment plate. A sliding rod is slidably connected in the adjustment groove, and the sliding rod is fixedly connected to the detection arm.

[0007] As a further optimized solution of the present invention, the adjustment groove is set to be arc-shaped, and the adjustment groove and the universal joint are located at the same center of the circle. When the detection arm rotates with the universal joint as the center of the circle, the sliding rod slides in the adjustment groove, so as to assist the detection arm in adjusting the angle, and facilitate the dynamic balance detection in the vertical direction and the dynamic balance detection with an inclination in the front and rear directions of the air spring on the suspension assembly main body.

[0008] As a further optimized solution of the present invention, first threaded rods are symmetrically arranged inside the lower frame, and first threaded sleeves are threadedly connected to the first threaded rods. A limiting rod is installed on the first threaded sleeve, and a limiting sleeve is slidably connected to the limiting rod. The limiting sleeve is fixedly connected to the sliding rod. The two groups of first threaded rods are connected by a pulley transmission mechanism. A first motor is also installed on the lower frame, and the output shaft of the first motor is fixedly connected to one of the groups of first threaded rods.

[0009] As a further optimized solution of the present invention, a lifting unit is provided inside the upper frame. The lifting unit includes a fixing frame installed inside the upper frame, and a second threaded rod is connected to the upper frame by a bearing. A second threaded sleeve is threadedly connected to the second threaded rod, and a lifting frame is installed on the second threaded sleeve. An installation frame is installed on the lifting frame, and a swinging unit is provided between the installation frame and the connecting beam. A second motor is also installed on the lifting frame.

[0010] As a further optimized solution of the present invention, the swinging unit includes a first connecting shaft bearing-connected inside the mounting frame, and a swing arm is mounted on the first connecting shaft. Both ends of the swing arm close to the connecting beam are rotatably connected to connecting seats through rotating shafts, and the connecting seats are fixedly connected to the connecting beam.

[0011] As a further optimized solution of the present invention, a connecting rod is installed inside the swing arm, and a movable frame is bearing-connected to the connecting rod. A second connecting shaft is bearing-connected to the mounting frame, and an inclined plate is installed at one end of the second connecting shaft close to the swing arm.

[0012] As a further optimized solution of the present invention, a rotating groove is formed on the inclined plate, and a rotating ball is movably connected inside the rotating groove. The rotating ball is fixedly connected to the movable frame.

[0013] As a further optimized solution of the present invention, a switching unit is provided between the second threaded rod and the second connecting shaft. The detection arm can be controlled by the switching unit to apply pressure to the suspension assembly main body in the up-and-down direction or alternately apply pressure in the left-and-right direction, so as to detect the dynamic balance data of the suspension assembly main body. The switching unit includes a first transmission shaft bearing-connected to the upper frame, and a first spline shaft is slidably connected inside the first transmission shaft. A first bevel gear is installed at one end of the first spline shaft close to the mounting frame. First gears are installed on both the first transmission shaft and the second threaded rod, and the first gears are meshed with each other. A second transmission shaft is bearing-connected to the mounting frame, and a second spline shaft is slidably connected inside the second transmission shaft. A second bevel gear is installed at one end of the second spline shaft close to the first spline shaft. Second gears are installed on both the second transmission shaft and the second connecting shaft, and the second gears are meshed with each other. A third bevel gear is provided between the first bevel gear and the second bevel gear, and the third bevel gear is fixedly connected to the output shaft of the second motor.

[0014] As a further optimized solution of the present invention, switching frames are bearing-connected to the outsides of the first spline shaft and the second spline shaft. An electric push rod is installed on the mounting frame, and the telescopic end of the electric push rod is fixedly connected to the switching frame.

[0015] The beneficial effects of the present invention are as follows: By changing the detection angle of the suspension assembly main body, the present invention performs dynamic balance detection in the vertical direction on the air spring of the suspension assembly main body, and dynamic balance detection with an inclination angle in the front-and-back direction, so as to realize multi-angle dynamic balance detection of the suspension assembly main body, and enable the detection arm to apply pressure from different angles to obtain the dynamic balance data of the suspension assembly main body. Description of the Drawings

[0016] Figure 1 is a three-dimensional structural schematic diagram of the present invention; Figure 2is a three-dimensional schematic diagram of the internal structure of the present invention; Figure 3 is a three-dimensional schematic diagram of a partial structure of the present invention; Figure 4 is a three-dimensional schematic diagram of the main body of the suspension assembly of the present invention; Figure 5 is a three-dimensional schematic diagram of the detection unit of the present invention; Figure 6 is of the present invention Figure 5 enlarged view of the structure at position A; Figure 7 is a three-dimensional schematic diagram of a partial structure of the detection arm, fixture and universal joint of the present invention; Figure 8 is a three-dimensional schematic diagram of a partial structure of the lifting unit and the swinging unit of the present invention; Figure 9 is a three-dimensional schematic diagram of a partial structure of the lifting unit, the swinging unit and the switching unit of the present invention; Figure 10 is a three-dimensional schematic diagram of a partial structure of the swinging unit of the present invention; Figure 11 is a three-dimensional schematic diagram of a partial structure of the switching unit of the present invention.

[0017] In the figure: 100, lower frame; 200, upper frame; 300, main body of suspension assembly; 301, suspension; 302, connecting frame; 303, air spring; 400, boss; 500, connecting beam; 600, detection unit; 601, detection arm; 602, fixture; 603, universal joint; 604, adjusting plate; 605, adjusting groove; 606, sliding rod; 607, first threaded rod; 608, first threaded sleeve; 609, limiting rod; 610, limiting sleeve; 611, pulley drive mechanism; 612, first motor; 700, lifting unit; 701, fixing frame; 702, second threaded rod; 703, second threaded sleeve; 704, lifting frame; 705, mounting frame; 706, second motor; 800, swinging unit; 801, first connecting shaft; 802, swing arm; 803, connecting seat; 804, connecting rod; 805, movable frame; 806, second connecting shaft; 807, inclined plate; 808, rotating ball; 900, switching unit; 901, first transmission shaft; 902, first spline shaft; 903, first bevel gear; 904, first gear; 905, second transmission shaft; 906, second spline shaft; 907, second bevel gear; 908, second gear; 909, switching frame; 910, electric push rod; 911, third bevel gear. Detailed implementation manners

[0018] Reference will now be made to example embodiments to discuss the subject matter described herein. It should be understood that discussing these embodiments is only to enable those skilled in the art to better understand and thus implement the subject matter described herein. Without departing from the scope of protection of the content of this specification, changes can be made to the functions and arrangements of the elements discussed. Each example can omit, substitute, or add various processes or components as needed. Additionally, the features described for some examples can also be combined in other examples.

[0019] As shown in Figures 1 to 4 figures, an axle suspension assembly testing bench includes a lower frame 100, an upper frame 200, a suspension assembly main body 300, a boss 400, and a connecting beam 500. The lower frame 100 and the upper frame 200 are fixedly connected. The boss 400 is fixedly connected to the lower frame 100. The suspension assembly main body 300 is placed on the boss 400 and is threadedly fixed between the suspension assembly main body 300 and the boss 400 by bolts. The connecting beam 500 is arranged at the top inside the lower frame 100, and there are two groups of connecting beams 500. Among them, the suspension assembly main body 300 includes a suspension 301. Connecting brackets 302 are symmetrically arranged on the suspension 301. An air spring 303 is provided between the suspension 301 and the connecting brackets 302.

[0020] As shown in Figures 5 to 7 figures, a detection unit 600 is provided between the connecting beam 500 and the suspension assembly main body 300 to perform static and dynamic balance detection on the suspension assembly main body 300 through the detection unit 600 to obtain dynamic balance detection data of the air spring 303.

[0021] Specifically, the detection unit 600 includes a detection arm 601 provided below each connecting beam 500. A clamp 602 is provided at one end of the detection arm 601 away from the connecting beam 500. A universal joint 603 is provided between the detection arm 601 and the clamp 602. The clamp 602 is used to clamp and fix the outside of the suspension 301, so as to facilitate the detection arm 601 to apply pressure to the suspension 301 and perform dynamic balance detection on the air spring 303.

[0022] Furthermore, an adjusting plate 604 is installed on the connecting beam 500. An adjusting groove 605 is provided on the adjusting plate 604. A slide bar 606 is slidably connected in the adjusting groove 605. The slide bar 606 is fixedly connected to the detection arm 601.

[0023] It should be noted that the adjustment groove 605 is set to be arc-shaped, and the adjustment groove 605 and the universal joint 603 are located at the same center of the circle. When the detection arm 601 rotates with the universal joint 603 as the center of the circle, the sliding rod 606 is slidably connected in the adjustment groove 605, so as to assist the detection arm 601 in angle adjustment, facilitate the dynamic balance detection of the air spring 303 on the suspension assembly main body 300 in the vertical direction, and the dynamic balance detection with inclination in the front-back direction, so as to realize the multi-angle dynamic balance detection of the suspension assembly main body 300.

[0024] Furthermore, according to Figure 8 and Figure 9 As shown, first threaded rods 607 are symmetrically arranged inside the lower frame 100, and a first threaded sleeve 608 is threadedly connected to the first threaded rod 607. A limiting rod 609 is installed on the first threaded sleeve 608, and a limiting sleeve 610 is slidably connected to the limiting rod 609. The limiting sleeve 610 is fixedly connected to the sliding rod 606. Among them, the two groups of first threaded rods 607 are connected by a pulley transmission mechanism 611, and a first motor 612 is also installed on the lower frame 100, and the output shaft of the first motor 612 is fixedly connected to one group of first threaded rods 607.

[0025] It should be understood that when the first motor 612 is driven to rotate, through the setting of the pulley transmission mechanism 611, the two groups of first threaded rods 607 are driven to rotate, so as to control the first threaded sleeve 608 to move on the first threaded rod 607, so that the limiting rod 609 moves, and the limiting sleeve 610 is controlled to push the detection arm 601 to move synchronously under the action of the movement of the limiting rod 609, so as to change the detection angle of the suspension assembly main body 300, so that the detection arm 601 applies pressure from different angles to obtain the dynamic balance data of the suspension assembly main body 300.

[0026] According to Figure 8 and Figure 9 As shown, a lifting unit 700 is arranged inside the upper frame 200. The lifting unit 700 includes a fixing frame 701 installed inside the upper frame 200, and a second threaded rod 702 is connected to the upper frame 200 by bearings. A second threaded sleeve 703 is threadedly connected to the second threaded rod 702, and a lifting frame 704 is installed on the second threaded sleeve 703. An installation frame 705 is installed on the lifting frame 704, and a swing unit 800 is arranged between the installation frame 705 and the connecting beam 500. A second motor 706 is also installed on the lifting frame 704.

[0027] Specifically, when driving the second threaded rod 702 to rotate, the second threaded sleeve 703 moves up and down outside the second threaded rod 702, so as to facilitate controlling the lifting frame 704 to move up and down, and controlling the two groups of detection arms 601 to apply synchronous upward and downward pressure to detect the dynamic balance of the suspension assembly main body 300, so that the two detection arms 601 apply uniform pressure to the suspension assembly main body 300, so that the pressures received by the suspension assembly main body 300 are the same, improving the accuracy of the detection data.

[0028] Further, according to Figures 8 to 10 As shown, the swing unit 800 includes a first connecting shaft 801 bearing-connected in the mounting frame 705, and a swing arm 802 is mounted on the first connecting shaft 801. Both ends of the swing arm 802 close to the connecting beam 500 are rotatably connected with connecting seats 803 through rotating shafts, and the connecting seats 803 are fixedly connected with the connecting beam 500. Through the arrangement of the swing arm 802, when the swing arm 802 rotates with the first connecting shaft 801 as the rotation point, the two detection arms 601 are controlled to apply pressure to the suspension assembly main body 300 in the left and right directions, so as to detect the dynamic balance data of the suspension assembly main body 300 when applying pressure to the suspension assembly main body 300 in the left and right directions.

[0029] Wherein, a connecting rod 804 is installed in the swing arm 802, and a movable frame 805 is bearing-connected to the connecting rod 804. A second connecting shaft 806 is bearing-connected to the mounting frame 705, and an inclined plate 807 is installed at one end of the second connecting shaft 806 close to the swing arm 802. A rotating groove is opened on the inclined plate 807, and a rotating ball 808 is movably connected in the rotating groove, and the rotating ball 808 is fixedly connected with the movable frame 805.

[0030] It should be added that when driving the second connecting shaft 806 to rotate, the inclined plate 807 is controlled to rotate synchronously. When the inclined plate 807 rotates, it squeezes the swing arm 802 in the left and right directions, causing the swing arm 802 to swing reciprocally, controlling the detection arm 601 to swing synchronously, so as to alternately squeeze and apply force to the left and right sides of the suspension assembly main body 300, and detecting the dynamic balance data of the suspension assembly main body 300.

[0031] According to Figures 8 to 11 As shown, a switching unit 900 is provided between the second threaded rod 702 and the second connecting shaft 806, so as to control the detection arm 601 to apply pressure to the suspension assembly main body 300 in the up and down direction or alternately apply pressure in the left and right direction through the switching unit 900, so as to detect the dynamic balance data of the suspension assembly main body 300.

[0032] Specifically, the switching unit 900 includes a first transmission shaft 901 bearing-connected to the upper frame 200. A first spline shaft 902 is slidably connected inside the first transmission shaft 901. A first bevel gear 903 is installed at one end of the first spline shaft 902 close to the mounting bracket 705. First gears 904 are installed on both the first transmission shaft 901 and the second threaded rod 702, and the first gears 904 are meshed with each other.

[0033] In addition, a second transmission shaft 905 is bearing-connected to the mounting bracket 705. A second spline shaft 906 is slidably connected inside the second transmission shaft 905. A second bevel gear 907 is installed at one end of the second spline shaft 906 close to the first spline shaft 902. Second gears 908 are installed on both the second transmission shaft 905 and the second connecting shaft 806, and the second gears 908 are meshed with each other. Among them, a third bevel gear 911 is provided between the first bevel gear 903 and the second bevel gear 907, and the third bevel gear 911 is fixedly connected to the output shaft of the second motor 706.

[0034] Furthermore, switching brackets 909 are bearing-connected to the outside of the first spline shaft 902 and the second spline shaft 906. An electric push rod 910 is installed on the mounting bracket 705, and the telescopic end of the electric push rod 910 is fixedly connected to the switching bracket 909.

[0035] It should be noted that when the second motor 706 is driven to rotate, the third bevel gear 911 rotates synchronously. At this time, the third bevel gear 911 is in an idle state. When the electric push rod 910 controls the switching bracket 909 to move, the first bevel gear 903 and the second bevel gear 907 are controlled to move up and down, so as to facilitate controlling the meshing connection between the first bevel gear 903 and the third bevel gear 911, or the meshing connection between the second bevel gear 907 and the third bevel gear 911, thereby driving the first spline shaft 902 or the second spline shaft 906 to rotate, causing the first transmission shaft 901 or the second transmission shaft 905 to rotate, so as to control the second threaded rod 702 or the second connecting shaft 806 to rotate, thereby driving the lifting unit 700 or the swinging unit 800 to work, and performing a dynamic balance test on the suspension assembly main body 300.

[0036] The above describes the embodiments of the specific implementation manner, but this embodiment is not limited to the above specific implementation manner. The above specific implementation manner is only illustrative and not restrictive. Under the inspiration of this embodiment, those of ordinary skill in the art can also make many forms, all of which fall within the protection scope of this embodiment.

Claims

1. An axle suspension assembly testing bench, characterized in that, It includes a lower frame (100), an upper frame (200), a suspension assembly main body (300), a boss (400) and a connecting beam (500). The suspension assembly main body (300) is placed on the boss (400). The connecting beams (500) are symmetrically arranged inside the lower frame (100). The suspension assembly main body (300) includes a suspension (301). Connecting brackets (302) are symmetrically arranged on the suspension (301). An air spring (303) is provided between the suspension (301) and the connecting brackets (302). A detection unit (600) is provided between the connecting beam (500) and the suspension assembly main body (300) to perform dynamic and static balance detection on the suspension assembly main body (300) through the detection unit (600) to obtain dynamic balance detection data of the air spring (303). The detection unit (600) includes a detection arm (601) provided below each connecting beam (500). A clamp (602) is provided at one end of the detection arm (601) away from the connecting beam (500). A universal joint (603) is provided between the detection arm (601) and the clamp (602). The clamp (602) is used to clamp and fix the outside of the suspension (301), so as to facilitate the detection arm (601) to apply pressure to the suspension (301) and perform dynamic balance detection on the air spring (303).

2. The axle suspension assembly testing bench according to claim 1, wherein, An adjusting plate (604) is installed on the connecting beam (500), and an adjusting groove (605) is formed in the adjusting plate (604). A sliding rod (606) is slidably connected in the adjusting groove (605), and the sliding rod (606) is fixedly connected to the detection arm (601).

3. The axle suspension assembly testing bench according to claim 2, characterized in that, The adjusting groove (605) is set to be arc-shaped. The adjusting groove (605) and the universal joint (603) are located at the same center of the circle. When the detection arm (601) rotates with the universal joint (603) as the center of the circle, the sliding rod (606) is slidably connected in the adjusting groove (605), so as to assist the detection arm (601) in angle adjustment, facilitating the dynamic balance detection of the air spring (303) on the suspension assembly main body (300) in the vertical direction and the dynamic balance detection with an inclination in the front-back direction.

4. The axle suspension assembly testing bench according to claim 2, characterized in that, First threaded rods (607) are symmetrically arranged inside the lower frame (100). A first threaded sleeve (608) is threadedly connected to the first threaded rod (607). A limiting rod (609) is installed on the first threaded sleeve (608). A limiting sleeve (610) is slidably connected to the limiting rod (609). The limiting sleeve (610) is fixedly connected to the sliding rod (606). The two groups of first threaded rods (607) are connected by a pulley transmission mechanism (611). A first motor (612) is also installed on the lower frame (100), and the output shaft of the first motor (612) is fixedly connected to one group of the first threaded rods (607).

5. The axle suspension assembly testing bench according to claim 1, characterized in that, A lifting unit (700) is provided inside the upper frame (200). The lifting unit (700) includes a fixed frame (701) installed inside the upper frame (200), and a second threaded rod (702) is connected between the fixed frame (701) and the upper frame (200) by bearings. A second threaded sleeve (703) is threadedly connected to the second threaded rod (702), and a lifting frame (704) is installed on the second threaded sleeve (703). An installation frame (705) is installed on the lifting frame (704), and a swing unit (800) is provided between the installation frame (705) and the connecting beam (500). A second motor (706) is also installed on the lifting frame (704).

6. The axle suspension assembly testing bench according to claim 5, characterized in that, The swing unit (800) includes a first connecting shaft (801) connected to the inside of the installation frame (705) by bearings, and a swing arm (802) is installed on the first connecting shaft (801). Connecting seats (803) are rotatably connected to both ends of the swing arm (802) close to the connecting beam (500) through rotating shafts, and the connecting seats (803) are fixedly connected to the connecting beam (500).

7. The axle suspension assembly testing bench according to claim 6, characterized in that, A connecting rod (804) is installed inside the swing arm (802), and a movable frame (805) is connected to the connecting rod (804) by bearings. A second connecting shaft (806) is connected to the installation frame (705) by bearings, and an inclined plate (807) is installed at one end of the second connecting shaft (806) close to the swing arm (802).

8. The axle suspension assembly testing bench according to claim 7, characterized in that, A rotating groove is formed in the inclined plate (807), and a rotating ball (808) is movably connected to the rotating groove. The rotating ball (808) is fixedly connected to the movable frame (805).

9. The axle suspension assembly testing bench according to claim 7, wherein, A switching unit (900) is provided between the second threaded rod (702) and the second connecting shaft (806) to control the detection arm (601) to apply pressure to the suspension assembly main body (300) in the up and down direction or alternately in the left and right direction through the switching unit (900), so as to detect the dynamic balance data of the suspension assembly main body (300). The switching unit (900) includes a first transmission shaft (901) bearing-connected to the upper frame (200), and a first spline shaft (902) is slidably connected inside the first transmission shaft (901). A first bevel gear (903) is installed at one end of the first spline shaft (902) close to the mounting bracket (705). First gears (904) are installed on both the first transmission shaft (901) and the second threaded rod (702), and the first gears (904) are meshed with each other. A second transmission shaft (905) is bearing-connected to the mounting bracket (705), and a second spline shaft (906) is slidably connected inside the second transmission shaft (905). A second bevel gear (907) is installed at one end of the second spline shaft (906) close to the first spline shaft (902). Second gears (908) are installed on both the second transmission shaft (905) and the second connecting shaft (806), and the second gears (908) are meshed with each other. A third bevel gear (911) is provided between the first bevel gear (903) and the second bevel gear (907), and the third bevel gear (911) is fixedly connected to the output shaft of the second motor (706).

10. The axle suspension assembly testing bench according to claim 9, characterized in that, Switching frames (909) are bearing-connected to the outsides of the first spline shaft (902) and the second spline shaft (906). An electric push rod (910) is installed on the mounting bracket (705), and the telescopic end of the electric push rod (910) is fixedly connected to the switching frame (909).

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