An online back emf zero detection device

Abstract

The application discloses an online counter electromotive force zero point detection device, which comprises a base, a first device, a second device, a counter electromotive force zero point detector and a multi-gear electric drive assembly controller. The first device is used for positioning, lifting, automatic oil injection and extraction and weighing of a tray and the multi-gear electric drive assembly. The second device is used for clamping the multi-gear electric drive assembly on the first device, and is used for butt joint with a spline shaft extended from the multi-gear electric drive assembly and butt joint with three-phase copper bars on the multi-gear electric drive assembly. The counter electromotive force zero point detector is used for detecting counter electromotive force and zero point of the multi-gear electric drive assembly. The multi-gear electric drive assembly controller is connected with the multi-gear electric drive assembly and is used for controlling the work of an oil pump and gear shifting operation in the multi-gear electric drive assembly. The use of the device greatly improves the detection efficiency of the counter electromotive force zero point detection on the multi-gear electric drive assembly assembly line, optimizes the detection process, and greatly improves the reliability of the detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical manufacturing, in particular to an online back electromotive force zero point detection device. BACKGROUND

[0002] Currently, the detection of the back electromotive force zero point of the motor mainly has the following two forms:

[0003] The first form is to use a small test bench, put the motor assembly or stator rotor on the small test bench, manually or automatically butt joint the rotating drag device to the rotor, manually connect the test wire harness, directly drag the rotor to rotate stably and detect the back electromotive force zero point. This type of detection device is more convenient for the detection of simple motor structure, but it is not suitable for the detection of complex multi-gear electric drive assembly with certain assembly requirements.

[0004] The second form is to use a large test bench, set up a large area near the production line, which contains a lubricating oil filling system, a weighing system and various rotating butt joints, pipeline systems, manually hoist the product from the production line to the test bench, and then manually or automatically butt joint various pipelines to detect the back electromotive force zero point. This type of detection device occupies a large area, is troublesome to hoist the product, and has low detection efficiency, so it is not suitable for detection of mass production and high rhythm production line. SUMMARY

[0005] From the above introduction of the prior art, it can be seen that the existing back electromotive force zero point measurement device cannot meet the detection of complex multi-gear electric drive products for small test benches, and the large test bench has the problems of large occupied area and low detection efficiency. In order to solve the detection of the back electromotive force zero point of the complex multi-gear electric drive assembly, the present application provides an online back electromotive force zero point detection device which is compact in structure, high in detection efficiency, reliable in detection data and will not cause adverse effects on the product. The device can fully meet the use requirements.

[0006] To solve the above technical problems, the present application realizes the following technical scheme:

[0007] An online back electromotive force zero point detection device, the back electromotive force zero point detection device comprises:

[0008] a base;

[0009] a first device mounted on the base for positioning, lifting, automatic oil injection and oil extraction and weighing of the tray and the multi-gear electric drive assembly;

[0010] The second device is mounted on the base and is used to clamp the multi-speed electric drive assembly on the first device, connect with the spline shaft extending from the multi-speed electric drive assembly, and connect with the three-phase copper busbar on the multi-speed electric drive assembly.

[0011] A back EMF zero-point measuring instrument is mounted on the base and is used to detect the back EMF and zero point of the multi-stage electric drive assembly.

[0012] A multi-speed electric drive assembly controller is mounted on the base and connected to the multi-speed electric drive assembly. It is used to control the operation of the oil pump and the shifting operation in the multi-speed electric drive assembly.

[0013] As a further optimization of the present invention, the first device includes:

[0014] A platform scale, wherein the platform scale is installed in a clearance groove at the top of the base, and the position of the platform scale relative to the clearance groove in the height and horizontal direction is adjustable;

[0015] A lifting and positioning assembly is installed on the top of the platform scale. The lifting and positioning assembly is used to position and lift the pallet and the multi-speed electric drive assembly.

[0016] An automatic oil injection and extraction assembly is mounted on the base and is used to inject and extract oil into the multi-speed electric drive assembly positioned on the lifting and positioning assembly.

[0017] As a further optimization of the present invention, a height adjustment structure for adjusting the height position of the platform scale is installed on the bottom surface of the platform scale; the height adjustment structure includes a clamping block, a screw rod is provided through the middle of the clamping block, the top of the screw rod is threaded to the bottom of the platform scale, a nut and a disc are fixed at the bottom of the screw rod below the clamping block, bolt holes are opened on both sides of the clamping block, and a first bolt fixed in the clearance groove is installed in the bolt hole, the diameter of the bolt hole is larger than the diameter of the first bolt.

[0018] As a further optimization of the present invention, a horizontal adjustment structure for adjusting the horizontal position of the platform scale is installed in the clearance groove; the horizontal adjustment structure includes an arc-shaped clamping block, which is fixed in the clearance groove by a second bolt, and the arc-shaped clamping block has multiple first horizontal adjustment bolts with different angles passing through it in the horizontal direction, which can be adjusted to make tight contact with the outer circular surface of the disc.

[0019] As a further optimization of the present invention, the lifting and positioning assembly includes a lifting and fixing frame, which is fixed to the platform scale by a connecting base. A lifting plate is installed on the top of the lifting and fixing frame by a telescopic sleeve. A lifting cylinder for driving the lifting plate to rise and fall is installed on the lifting and fixing frame. A positioning pin for positioning the pallet is installed on the top surface of the lifting plate.

[0020] As a further optimization of the present invention, the horizontal position of the lifting and fixing frame relative to the connecting base is adjustable; a large hole is provided on the support plate at the bottom of the lifting and fixing frame, and the support plate is connected to the threaded hole on the connecting base by a third bolt passing through the large hole, the diameter of the large hole being larger than the diameter of the third bolt; the connecting base on the outer side of the support plate is equipped with fixing blocks in two vertical directions, and a second horizontal adjusting bolt is horizontally threaded through the fixing block, the second horizontal adjusting bolt being able to be adjusted to make tight contact with the support plate.

[0021] As a further optimization of the present invention, the automatic oil injection and extraction assembly includes a fixed rod, which is installed on the base and passes through the inside of the lifting and positioning assembly. A lifting cylinder and a linear guide rail are installed on the fixed rod through a first fixed connecting seat. An oil injection and extraction docking joint is slidably connected to the linear guide rail through a first movable connecting seat. The lifting cylinder is drivenly connected to the first movable connecting seat. The top of the lifting and positioning assembly is provided with a notch for the oil injection and extraction docking joint to be lifted, lowered, and docked. The automatic oil injection and extraction assembly is staggered from the platform scale and the lifting and positioning assembly in terms of height.

[0022] As a further optimization of the present invention, a card reader is installed on the lifting and fixing frame for reading and writing the code carrier on the tray.

[0023] As a further optimization of the present invention, the second device includes:

[0024] Fixed support;

[0025] A movable clamping assembly is mounted on the base via the fixed support and is used to clamp the multi-stage electric drive assembly on the first device.

[0026] A rotary drive assembly, which is mounted on the movable clamping assembly, is used to mate with the splined shaft on the multi-speed electric drive assembly;

[0027] The three-phase electrical connection assembly is mounted on the movable clamping assembly and is used to connect with the three-phase copper busbar on the multi-speed electric drive assembly.

[0028] As a further optimization of the present invention, the movable clamping assembly includes a fixed frame mounted on the top of the fixed support, a first movable frame slidably connected to the top of the fixed frame, a first drive cylinder for driving the first movable frame to slide back and forth relative to the fixed frame, and a hydraulic clamping mechanism mounted on the first movable frame for clamping the multi-stage electric drive assembly.

[0029] As a further optimization of the present invention, a first slide rail is installed on the top of the fixed frame, and limiters are installed at both ends of the first slide rail; the first drive cylinder is installed on the side of the fixed frame, and the output end of the first drive cylinder is drivenly connected to the first movable frame; a drag chain is installed between the fixed frame and the first movable frame.

[0030] As a further optimization of the present invention, a plurality of hydraulic clamping mechanisms are arranged circumferentially on the front end face of the first movable frame. Each hydraulic clamping mechanism includes a fixed seat mounted on the front end face of the first movable frame, a hydraulic cylinder mounted on the fixed seat, and a clamping block with one end drivenly connected to the hydraulic cylinder. The middle part of the clamping block is rotatably connected to the fixed seat through a rotating shaft and a bearing seat.

[0031] As a further optimization of the present invention, the rotary drive assembly includes a second movable frame slidably connected to the first movable frame, a first servo motor for driving the second movable frame to slide back and forth relative to the first movable frame, and a second servo motor mounted on the second movable frame. The output end of the second servo motor is connected to a docking sleeve for docking with the spline shaft on the multi-speed electric drive assembly via a telescopic component. The first movable frame has a through hole for the docking sleeve to pass through.

[0032] As a further optimization of the present invention, a second slide rail is installed on the top of the first movable frame; the first servo motor is installed on the first movable frame, and the output end of the first servo motor is drivenly connected to the second movable frame through a gear and a rack; the second servo motor is installed on the second movable frame through a rotary bearing structure, and the output end of the second servo motor is connected to a docking sleeve through the telescopic component.

[0033] As a further optimization of the present invention, the telescopic component includes a rotating shaft, one end of which is connected to the output end of the second servo motor via a coupling, and the other end is connected to the docking sleeve; a limiting piece is installed in the middle of the rotating shaft, and a first spring is sleeved on the rotating shaft between the limiting piece and the coupling, and there is a gap between the inner end of the rotating shaft and the inside of the coupling.

[0034] As a further optimization of the present invention, the three-phase electrical connection assembly includes a fixed bracket mounted on the first movable frame, a second drive cylinder mounted on the fixed bracket, a mounting plate slidably connected below the fixed bracket, and a connection structure mounted on the mounting plate, wherein the mounting plate is drivenly connected to the output end of the second drive cylinder.

[0035] As a further optimization of the present invention, the docking structure includes a nylon connecting plate mounted on the mounting plate, comb-shaped guide strips mounted side by side on the nylon connecting plate, a connecting shaft mounted between two adjacent guide strips, a second spring sleeved on the connecting shaft, and a docking copper sleeve mounted on the head of the connecting shaft.

[0036] As a further optimization of the present invention, the second driving cylinder is mounted on the fixed bracket via a second fixed connecting seat, and the output end of the second driving cylinder is drivenly connected to the mounting plate via a second movable connecting seat; a slide is installed below the fixed bracket, and a third slide rail is slidably connected below the slide, and the third slide rail is fixedly connected to the mounting plate; the mounting plate is fixedly connected to the third slide rail via a rib plate and a fixed plate.

[0037] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] (1) This invention provides an online detection device for detecting the zero point of the back EMF of a motor on a multi-speed electric drive assembly line. This device integrates multiple functions such as positioning, lifting, automatic oil injection and extraction, clamping, rotational docking, three-phase electrical docking, and back EMF zero-point detection. It has a compact overall structure, small footprint, reliable data detection, and comprehensive functions, without any adverse effects on the product testing process. This device allows users to avoid using large offline test benches, significantly reducing the space and investment costs required for the assembly line and significantly improving the testing efficiency and quality of such assembly lines. This online detection device can also be widely applied to back EMF detection of various multi-speed electric drive assemblies.

[0039] (2) The platform scale is adjustable in both height and horizontal direction. The height and horizontal adjustment structures allow for precise adjustment of the platform scale's position, ensuring weighing accuracy and increasing the device's flexibility and adaptability. The horizontal position of the lifting and positioning assembly's lifting and fixing frame relative to the connecting base is also adjustable. This prevents the need for further adjustments to the platform scale later, as it is a high-precision testing device with strict requirements for position and horizontal alignment. Once the platform scale is installed and adjusted, further adjustments are not recommended.

[0040] (3) The lifting and positioning assembly can automatically position and lift the pallet and the multi-speed electric drive assembly, improving production efficiency. The automatic oil injection and extraction assembly can automatically perform oil injection and extraction operations on the multi-speed electric drive assembly positioned on the lifting and positioning assembly, reducing manual intervention and improving operational efficiency and accuracy. The card reader installed on the lifting and fixing frame can read the code information on the pallet, realizing intelligent management and traceability. Both the lifting and positioning assembly and the automatic oil injection and extraction assembly are equipped with switch components to detect the position status, ensuring the accuracy and safety of the operation process.

[0041] (4) The hydraulic clamping mechanism uses hydraulic power as its power source, providing large clamping force and good stability, thus ensuring the stability of the multi-speed electric drive assembly during rotational dragging. The docking sleeve in the rotary drive assembly has a certain floating space in the axial and radial directions, ensuring reliable docking with the spline shaft on the multi-speed electric drive assembly and improving the success rate of spline docking. The docking copper sleeve in the three-phase electric docking assembly, through spring pressure and dimensional matching, ensures tight contact with the three-phase copper busbar on the multi-speed electric drive assembly, avoiding short circuits and open circuits.

[0042] (5) The present invention can accurately control the oil pump operation and gear shifting operation of the multi-speed electric drive assembly through the multi-speed electric drive assembly controller and the back EMF zero-point measuring instrument, and detect the back EMF and zero-point data in real time to ensure the accuracy and reliability of the detection results. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the back EMF zero-point detection device of the present invention.

[0044] Figure 2 This is a schematic diagram of the application structure of the back EMF zero-point detection device of the present invention on a production line.

[0045] Figure 3 This is a schematic diagram of the structure of the first device of the present invention.

[0046] Figure 4 This is a schematic diagram of the assembly structure of the platform scale and lifting positioning component of the present invention.

[0047] Figure 5 for Figure 4 A schematic diagram of the longitudinal cross-sectional structure.

[0048] Figure 6 for Figure 4 A schematic diagram of the transverse cross-sectional structure.

[0049] Figure 7 for Figure 4 A magnified structural diagram at point A in the diagram.

[0050] Figure 8 for Figure 5A magnified structural diagram at point B in the diagram.

[0051] Figure 9 This is a schematic diagram of the automatic oil injection and extraction assembly of the present invention.

[0052] Figure 10 This is a schematic diagram of the structure of the device of the present invention. Figure 1 .

[0053] Figure 11 This is a schematic diagram of the structure of the device of the present invention. Figure 2 .

[0054] Figure 12 for Figure 11 Enlarged structural diagram at point C.

[0055] Figure 13 This is a schematic diagram of the longitudinal cross-sectional structure of the device of the present invention.

[0056] Figure 14 for Figure 13 A magnified structural diagram at point D in the diagram.

[0057] Figure 15 for Figure 13 A magnified structural diagram at point E in the diagram.

[0058] Figure 16 for Figure 10 Enlarged structural diagram of the three-phase electrical connection assembly.

[0059] Figure 17 This is a bottom view of the three-phase electrical connection assembly of the present invention.

[0060] The diagram labels are as follows: 1. Base; 11. Clearance groove; 2. First device; 21. Platform scale; 22. Lifting and positioning assembly; 221. Lifting fixing frame; 222. Connecting base; 223. Telescopic sleeve; 224. Lifting plate; 2241. Positioning pin; 2242. Notch; 225. Lifting cylinder; 226. Support base plate; 227. Third bolt; 228. Fixing block; 229. Second leveling bolt; 23. Automatic oil injection and extraction assembly; 231. Fixing rod; 232. First fixed connecting seat; 233. Lifting cylinder; 234. Linear guide rail; 235. First movable connection. 236. Oil injection / extraction docking joint; 24. Height adjustment structure; 241. Clamping block; 242. Screw; 243. Disc; 244. Nut; 245. First bolt; 246. Bolt hole; 25. Horizontal adjustment structure; 251. Arc-shaped clamping block; 252. Second bolt; 253. First horizontal adjustment bolt; 26. Card reader; 3. Second device; 31. Fixed support; 32. Movable clamping assembly; 321. Fixed frame; 322. First movable frame; 3221. Through hole; 323. First drive cylinder; 324. Hydraulic clamping mechanism; 3241. 3242. Fixed seat; 3243. Hydraulic cylinder; 3244. Clamping block; 3245. Rotating shaft; 3246. Shaft seat; 325. First slide rail; 326. Limiter; 327. Cable chain; 33. Rotary drive assembly; 331. Second movable frame; 332. First servo motor; 333. Second servo motor; 334. Telescopic assembly; 3341. Rotating shaft; 3342. Coupling; 3343. Limiting piece; 3344. First spring; 3345. Clearance; 335. Connecting sleeve; 336. Second slide rail; 337. Gear; 338. Rack; 339. Rotary bearing structure; 34 1. Three-phase electrical connection assembly; 341. Fixed bracket; 342. Second drive cylinder; 343. Mounting plate; 3431. Rib plate; 3432. Fixed plate; 344. Nylon connecting plate; 345. Connection structure; 3451. Guide bar; 3452. Connecting shaft; 3453. Second spring; 3454. Connection copper sleeve; 346. Second fixed connecting seat; 347. Second movable connecting seat; 348. Slide seat; 349. Third slide rail; 4. Back EMF zero point measuring instrument; 5. Multi-speed electric drive assembly controller; 6. Tray; 7. Multi-speed electric drive assembly; 8. Conveyor roller; 9. Switch assembly. Detailed Implementation

[0061] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the accompanying drawings are for illustrative purposes only and should not be construed as limiting the present patent. For better illustration of this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present patent.

[0062] For measuring the back EMF zero point of a multi-speed electric drive assembly, according to the measurement requirements, the back EMF zero point of the motor must be measured under the premise that the motor rotor is stable at a certain speed and time. However, for multi-speed electric drive assemblies, due to their complex structure (two sets of motors), numerous shafts, and the influence of product assembly processes and cycle times, this equipment must have at least the following functions and devices to meet the above-mentioned rotor speed requirements:

[0063] (1) Lubricating oil filling / extraction function to ensure that the shaft system of the multi-speed electric drive assembly is lubricated with oil during high-speed rotation, and to avoid dry friction of the shaft system causing product damage; (2) Automatic lubricating oil filling docking function to ensure that different trays and multi-speed electric drive assemblies can automatically dock to complete the lubricating oil filling when they arrive at the work station of this equipment; (3) High-precision weighing device to weigh the products before lubricating oil filling and after lubricating oil extraction at this work station, so as to obtain the accurate weight of the residual lubricating oil in the product, and bind this data into the product for the convenience of subsequent operation and management of the product. (4) Stable shaft docking device and rotating device to automatically dock with the spline shaft of the multi-speed electric drive and drive the shaft system and motor rotor to rotate at high speed and stably. (5) Oil pump start and automatic gear shifting device. Because the multi-speed electric drive product has two motors and multiple shaft systems, and only one motor can be driven to rotate when the motor is driven to rotate through the shaft system, if it is necessary to drive the other motor to rotate, the gear must be shifted first. In addition, if the lubricating oil is required to lubricate normally, the product's oil pump needs to be started. Therefore, the product needs to be connected to electricity and the shift motor needs to be controlled and shifted. (6) Hydraulic clamping device, used to position and clamp the multi-speed electric drive assembly to avoid the vibration of the rotor and shaft system of the multi-speed electric drive assembly during high-speed rotation and testing from causing adverse effects on the carrier and roller conveyor. (7) Back EMF and zero point measuring device, used to detect the back EMF and zero point of the motor that is stable at a certain speed.

[0064] Please see Figures 1-2This embodiment provides an online back EMF zero-point detection device that is compact in structure, has high detection efficiency, provides reliable detection data, and does not adversely affect the product. It includes a base 1, a first device 2, a second device 3, a back EMF zero-point measuring instrument 4, a multi-stage electric drive assembly controller 5, and is also equipped with a hydraulic station, an electrical cabinet, and a lubricating oil filling machine.

[0065] The first device 2 includes a platform scale 21, a lifting and positioning assembly 22, an automatic oil injection and extraction assembly 23, and a card reader 26. A large clearance groove 11 is provided on the top of the base 1. The platform scale 21 is installed in the clearance groove 11, and its position relative to the clearance groove 11 in both height and horizontal direction is adjustable. The lifting and positioning assembly 22 is installed on top of the platform scale 21 and is used to position and lift the tray 6 and the multi-speed electric drive assembly 7. The automatic oil injection and extraction assembly 23 is installed on the base 1 and is used to inject and extract oil from the multi-speed electric drive assembly 7 positioned on the lifting and positioning assembly 22.

[0066] In some examples, the bottom surface of the platform scale 21 is equipped with four height adjustment structures 24 for adjusting the height position of the platform scale 21, and four level adjustment structures 25 for adjusting the horizontal position of the platform scale 21 are installed in the clearance groove 11. The height adjustment structures 24 and the level adjustment structures 25 are set in a one-to-one correspondence.

[0067] For details, please refer to Figure 7 and Figure 8 The height adjustment structure 24 includes a clamping block 241, with a screw 242 running through its center. The top of the screw 242 is threaded to the bottom of the platform scale 21. A nut 244 and a disc 243 are fixed to the bottom of the screw 242 below the clamping block 241. Bolt holes 246 are provided on both sides of the clamping block 241, and a first bolt 245 fixed in the clearance groove 11 is installed in the bolt holes 246. The diameter of the bolt holes 246 is larger than the diameter of the first bolt 245. The screw 242, nut 244, and disc 243 are integrally formed. By rotating the nut 244, the screw 242 is driven to screw in or out on the platform substrate, thereby adjusting the height of the platform scale 21. The larger diameter of the bolt holes 246 than the diameter of the first bolt 245 increases the horizontal movement space of the clamping block 241, thus providing the necessary conditions for adjusting the horizontal position of the platform scale 21. The aforementioned height adjustment structure 24, through components such as screw 242, nut 244 and disc 243, enables precise adjustment of the height position of the platform scale 21, which is easy to operate and has a wide adjustment range.

[0068] For details, please refer to Figure 7 and Figure 8The horizontal adjustment structure 25 includes an arc-shaped clamping block 251, which is fixed in the clearance groove 11 by a second bolt 252. Multiple first horizontal adjustment bolts 253 at different angles penetrate the arc-shaped clamping block 251 in the horizontal direction. These first horizontal adjustment bolts 253 can be adjusted to make tight contact with the outer surface of the disc 243. By rotating the first horizontal adjustment bolts 253 at different angles, the disc 243 can be moved in different directions, thereby adjusting the position of the platform scale 21 in terms of the water surface. After the final height and horizontal position are adjusted, the platform scale 21 is tightened by the clamping block 241 and the first bolts 245 to prevent it from tilting or being pulled upwards. The horizontal adjustment structure 25, through components such as the arc-shaped clamping block 251 and the first horizontal adjustment bolts 253, achieves precise adjustment of the horizontal position of the platform scale 21, ensuring the stability of the device in the horizontal direction.

[0069] In some examples, please refer to Figure 4 and Figure 5 The lifting and positioning assembly 22 includes a lifting and fixing frame 221. Connection holes are pre-machined on the weighing surface of the platform scale 21, and the connecting base 222 of the lifting and positioning assembly 22 is connected to the platform scale 21 through these connection holes. A lifting plate 224 is mounted on the top of the lifting and fixing frame 221 via a telescopic sleeve 223. A lifting cylinder 225 for driving the lifting plate 224 to rise and fall is mounted on the lifting and fixing frame 221. A switch assembly 9 for detecting the lifting position of the lifting plate 224 is also mounted on the lifting and fixing frame 221 to automate the device. A positioning pin 2241 for positioning the pallet 6 is mounted on the top surface of the lifting plate 224. The lifting and positioning assembly 22 includes components such as the lifting and fixing frame 221, the lifting plate 224, and the lifting cylinder 225. Through the coordinated operation of these components, the positioning and lifting of the pallet 6 and the multi-stage electric drive assembly 7 are achieved, improving the automation level of the device.

[0070] In some examples, please refer to Figure 3 A card reader 26 is installed on the lifting and fixing frame 221 for reading and writing the code carrier on the tray 6. The tray 6 has a code carrier that can store certain data, such as the specific number of the product on the tray 6 and various production information (such as tightening, gluing, oiling, weight, etc.). The cooperation between the code carrier and the card reader 26 enables each station on the assembly line to identify the product and record the assembly process of the product at that station.

[0071] In some examples, the horizontal position of the lifting and fixing frame 221 relative to the connecting base 222 is adjustable, further increasing the flexibility and adaptability of the device to meet the needs of multi-stage electric drive assemblies 7 of different sizes and shapes.

[0072] For details, please refer toFigure 6 The bottom support plate 226 of the lifting and fixing frame 221 has a large hole. The support plate 226 is connected to the threaded hole on the connecting base 222 by a third bolt 227 passing through the large hole. The diameter of the large hole is larger than the diameter of the third bolt 227. This fixing method ensures that the lifting and positioning frame has a certain amount of horizontal adjustment. The connecting base 222 on the outer side of the support plate 226 has fixing blocks 228 installed in two vertical directions. A second horizontal adjusting bolt 229 is horizontally threaded onto the fixing block 228. The second horizontal adjusting bolt 229 can be adjusted to make tight contact with the support plate 226. The horizontal adjusting bolts allow for a certain amount of adjustment and tightening of the lifting and positioning frame. These features ensure that the lifting and positioning frame has a certain degree of horizontal adjustment capability.

[0073] In some examples, please refer to Figure 9 The automatic oil injection and extraction assembly 23 includes a fixed rod 231, which is mounted on the base 1 and passes through the inside of the lifting and positioning assembly 22. A lifting cylinder 233 and a linear guide rail 234 are mounted on the fixed rod 231 through a first fixed connecting seat 346232. An oil injection and extraction docking joint 236 is slidably connected to the linear guide rail 234 through a first movable connecting seat 235. The lifting cylinder 233 is driven to connect with the first movable connecting seat 235. A switch assembly 9 for detecting the lifting position of the oil injection and extraction docking joint 236 is mounted on the first fixed connecting seat 346232 to realize the automation of this device. A notch 2242 is provided on the lifting plate 224 at the top of the lifting and positioning assembly 22 for the lifting and extraction docking joint 236 to be lifted and docked. The aforementioned automatic oil injection and extraction assembly 23 includes components such as a fixed rod 231, a lifting cylinder 233, a linear guide rail 234, and an oil injection and extraction docking joint 236. Through the coordinated work of these components, automatic oil injection and extraction of the multi-speed electric drive assembly 7 are realized, thereby improving the automation level of the production line.

[0074] Specifically, the oil filling and extraction docking joint 236 is connected to a lubricating oil filling machine via a pipeline. The lubricating oil filling machine is placed on the ground near the base 1. The filling machine contains a lubricating oil filling system, a lubricating oil extraction system, a clean oil tank, a dirty oil tank, a filtration system, and a replenishment system. It can realize the quantitative filling of lubricating oil and the filtration and recovery of lubricating oil. When the lubricating oil in the clean oil tank is insufficient, it can issue an alarm and automatically extract clean lubricating oil from a nearby oil tank to replenish it. The oil injection / extraction connector 236 can be designed as a floating quick-connect connector (female). Before this station, a vertically downward corresponding quick-connect connector (male) has been manually installed on the multi-speed electric drive assembly 7. When the multi-speed electric drive assembly 7 enters this station and is positioned along with the tray 6, the quick-connect connector (female) will be pushed by the lifting cylinder 233, passing through the notch 2242 on the lifting plate 224 and the clearance hole reserved on the tray 6, to automatically connect and lock with the quick-connect connector (male) on the multi-speed electric drive assembly 7. Subsequently, driven by the lubricating oil filling machine, precise quantitative automatic oil injection and subsequent automatic oil extraction can be achieved in this station. Moreover, the connection process between the quick-connect connector (female) and the quick-connect connector (male) is accurate and reliable, and there is no oil leakage during the insertion and removal process.

[0075] In some examples, the automatic oil injection and extraction assembly 23 is arranged separately from the platform scale 21 and the lifting and positioning assembly 22 in terms of height. Through reasonable design, the automatic oil injection and extraction assembly 23 is arranged separately from the platform scale 21 and the lifting and positioning assembly 22 in terms of height, which avoids mutual interference and improves the compactness and space utilization of the device.

[0076] After the above three components are integrated, the lifting and positioning component 22 can achieve precise positioning of the pallet 6 and the multi-speed electric drive assembly 7. The high-precision platform scale 21 actually weighs the weight of the lifting and positioning component 22, the weight of the pallet 6, and the weight of the multi-speed electric drive assembly 7. The weight of the automatic oil injection and extraction component 23 is not included in the weighing system. The automatic oil injection and extraction component 23 can normally perform oil injection and extraction operations on the multi-speed electric drive assembly 7, and the weight of the residual lubricating oil in the multi-speed electric drive assembly 7 after oil injection and extraction can be calculated by the difference between the two weighings. After the entire device is installed, when the pallet 6 carrying the multi-speed electric drive assembly 7 is transported from the conveyor roller 8 to this workstation, the lifting and positioning component 22 first lifts the pallet 6 and the multi-speed electric drive assembly 7. After the pallet 6 and the multi-speed electric drive assembly 7 are lifted by the lifting and positioning component 22, the platform scale 21 records the weight of all devices on it at this time. The platform scale 21 will record the weight of all devices on it again after the final product is automatically filled with lubricating oil and automatically extracted from the lubricating oil. The difference between the weight of the second weighing and the weight of the first weighing is the weight of the lubricating oil remaining in the product during operation at this workstation. This data will be recorded into the product's data chain through the read and write of the code carrier for subsequent operation of the product. This device can automatically perform oil filling and oil extraction operations on the products entering this workstation, and can monitor and record the weight before and after oil filling and oil extraction. This device has a compact structure, complete functions, convenient adjustment and maintenance, and reliable weight data detection.

[0077] Please see Figure 10 and Figure 11 The second device 3 includes a fixed support 31, a movable clamping assembly 32, a rotary drive assembly 33, and a three-phase electrical connection assembly 34. The movable clamping assembly 32 is used to clamp the multi-stage electric drive assembly 7, the rotary drive assembly 33 is used to connect with the splined shaft on the multi-stage electric drive assembly 7, and the three-phase electrical connection assembly 34 is used to connect with the three-phase copper busbar on the multi-stage electric drive assembly 7. This device has a compact overall structure, reasonable layout, stable clamping, reliable rotary connection, and can perform automatic three-phase electrical connection. This device can greatly reduce the space required for such equipment and improve the reliability of the connection process. This device is particularly suitable for automatic inspection stations or test benches on multi-stage electric drive assembly 7 assembly lines.

[0078] In some examples, the movable clamping assembly 32 includes a fixed frame 321 mounted on top of the fixed support 31, a first movable frame 322 slidably connected to the top of the fixed frame 321, a first drive cylinder 323 for driving the first movable frame 322 to slide back and forth relative to the fixed frame 321, and a hydraulic clamping mechanism 324 mounted on the first movable frame 322 for clamping the multi-stage electric drive assembly 7.

[0079] The fixed frame 321 has a first slide rail 325 mounted on its top, with limiters 326 installed at both its front and rear ends. A first drive cylinder 323 is mounted on the side of the fixed frame 321, and its output is connected to a first movable frame 322. A cable chain 327 is installed between the fixed frame 321 and the first movable frame 322. (See also...) Figure 15 Multiple hydraulic clamping mechanisms 324 are circumferentially arranged on the front end face of the first movable frame 322. Each hydraulic clamping mechanism 324 includes a fixed base 3241 mounted on the front end face of the first movable frame 322, a hydraulic cylinder 3242 mounted on the fixed base 3241, and a clamping block 3243 with one end drivenly connected to the hydraulic cylinder 3242. The middle part of the clamping block 3243 is rotatably connected to the fixed base 3241 through a rotating shaft 3244 and a bearing 3245. The hydraulic cylinder 3242 uses hydraulic power as its power source. The hydraulic clamping force is greater than that of the pneumatic cylinder, ensuring the stability of the multi-speed electric drive assembly 7 during the high-speed shaft dragging process in the subsequent testing process. A switch assembly 9 is also provided on the fixed base 3241 for detecting the position and status of the clamping block 3243.

[0080] Based on the posture of the multi-speed electric drive assembly 7 on the pallet 6 and the conveying direction of the pallet 6 on the conveying roller 8, the entire device is arranged on the side of the conveying roller 8, and the positioning pin 2241 on the pallet 6 is inserted into the positioning hole on the multi-speed electric drive assembly 7. When the multi-speed electric drive assembly 7 enters the inspection station with the pallet 6, the hydraulic clamping mechanism 324, under the action of the first drive cylinder 323 and the first slide rail 325, abuts against the multi-speed electric drive assembly 7. Then, under the push and pull of the hydraulic cylinder 3242, the clamping block 3243 of the hydraulic clamping mechanism 324 tightly hooks the protruding plane on the multi-speed electric drive assembly 7, thereby clamping and locking the multi-speed electric drive assembly 7.

[0081] In some examples, after the multi-speed electric drive assembly 7 is clamped and locked by the aforementioned movable clamping assembly 32, a rotary drive assembly 33 capable of rotating and dragging the internal shaft system of the multi-speed electric drive assembly 7 is required to complete the dragging of the shaft system. Please refer to... Figure 13 The rotary drive assembly 33 includes a second movable frame 331 slidably connected to the first movable frame 322, a first servo motor 332 for driving the second movable frame 331 to slide back and forth relative to the first movable frame 322, and a second servo motor 333 mounted on the second movable frame 331. The front end of the output end of the second servo motor 333 is connected to a docking sleeve 335 for docking with the spline shaft on the multi-speed electric drive assembly 7 through a telescopic assembly 334. The first movable frame 322 has a through hole 3221 for the docking sleeve 335 to pass through.

[0082] The first movable frame 322 has a second slide rail 336 mounted on its top; a first servo motor 332 is mounted on the first movable frame 322, and the output of the first servo motor 332 is connected to the second movable frame 331 via a gear 337 and a rack 338. (See also...) Figure 12 The second servo motor 333 is mounted on the second movable frame 331 via a rotating shaft 3341 and a bearing structure 339. The output end of the second servo motor 333 is connected to a mating sleeve 335 via a telescopic component 334. For details, please refer to [link / reference]. Figure 14 The telescopic assembly 334 includes a rotating shaft 3341. One end of the rotating shaft 3341 is connected to the output end of the second servo motor 333 via a coupling 3342, and the other end is connected to a mating sleeve 335. A limit plate 3343 is installed in the middle of the rotating shaft 3341. A first spring 3344 is sleeved on the rotating shaft 3341 between the limit plate 3343 and the coupling 3342. There is a gap 3345 between the inner end of the rotating shaft 3341 and the inside of the coupling 3342. A switch assembly 9 is also provided on the bearing structure 339 of the rotating shaft 3341 for detecting the telescopic position and state of the rotating shaft 3341.

[0083] Under the action of the first servo motor 332, the rotational force of the first servo motor 332 can be converted into a stable forward and backward pushing force for the remaining mechanisms through the conversion of gear 337, rack 338, and second slide rail 336. The forward and backward pushing force of the first servo motor 332 is used to provide a precise and stable forward and backward pushing force for the second servo motor 333, which in turn provides the angular rotational force required for the spline docking process and subsequently provides a continuous and stable rotational force for the shaft system of the multi-stage electric drive assembly 7. The second servo motor 333, the rotating shaft 3341, the first spring 3344, and the docking sleeve 335 are all fixed on the bearing structure 339 of the rotating shaft 3341, and the tolerance range of each part is matched to ensure that the final docking sleeve 335 has a certain floating space in the axial and radial directions. This ensures that the docking sleeve 335 can reliably dock with the spline shaft on the multi-stage electric drive assembly 7, greatly improving the success rate of spline docking.

[0084] In some examples, please refer to Figure 16 and Figure 17The three-phase electrical connection assembly 34 includes a fixed bracket 341 mounted on a first movable frame 322, a second drive cylinder 342 mounted on the fixed bracket 341, a mounting plate 343 slidably connected below the fixed bracket 341, and a connection structure 345 mounted on the mounting plate 343. The mounting plate 343 is drivenly connected to the output end of the second drive cylinder 342. The second drive cylinder 342 is mounted on the fixed bracket 341 via a second fixed connecting seat 346232, and the output end of the second drive cylinder 342 is drivenly connected to the mounting plate 343 via a second movable connecting seat 347. A slide block 348 is mounted below the fixed bracket 341, and a third slide rail 349 is slidably connected below the slide block 348. The third slide rail 349 is fixedly connected to the mounting plate 343. The mounting plate 343 is fixedly connected to the third slide rail 349 via a rib plate 3431 and a fixed plate 3432. By pushing the second drive cylinder 342 and acting on the third slide rail 349, the docking copper sleeve 3454 and other movable connecting parts can extend and retract to complete the docking with the three-phase copper busbar on the multi-speed electric drive assembly 7. The fixed bracket 341 is also equipped with a switch assembly 9 for detecting the sliding position and status of the mounting plate 343.

[0085] The docking structure 345 includes a nylon connecting plate 344 mounted on a mounting plate 343, comb-shaped guide bars 3451 mounted side-by-side on the nylon connecting plate 344, a connecting shaft 3452 installed between two adjacent guide bars 3451, a second spring 3453 sleeved on the connecting shaft 3452, and a docking copper sleeve 3454 installed at the head of the connecting shaft 3452. The nylon connecting plate 344 is an insulated non-metallic component, and the conductive current is mainly conducted through the connecting shaft 3452 and the docking copper sleeve 3454. To prevent short circuits and open circuits, the nylon connecting plate 344 is equipped with comb-shaped guide bars 3451 to ensure guidance and isolation between the conductive components. To prevent the mating surfaces of the copper busbar and the three-phase copper busbar of the multi-speed electric drive assembly 7 from being uneven or unreliable, a second spring 3453 is installed on the connecting shaft 3452, and the dimensional fit between the various parts is used to ensure that the copper sleeve 3454 has a certain angle of floating and a certain spring pressure during the mating process with the multi-speed electric drive assembly 7, so as to ensure that the mating surfaces of the copper sleeve and the three-phase copper busbar on the multi-speed electric drive assembly 7 can be tightly fitted.

[0086] In actual operation, the first drive cylinder 323 first pushes the first movable frame 322 and all devices on it forward. Then, the hydraulic clamping mechanism 324 clamps the multi-speed electric drive assembly 7. Next, the first servo motor 332 pushes the second servo motor 333 forward to connect the docking sleeve 335 with the extended spline shaft of the multi-speed electric drive assembly 7. After docking, the second servo motor 333 drives the shaft system and motor rotor in the multi-speed electric drive assembly 7 to rotate at a certain speed, which facilitates the subsequent measurement of the motor's back electromotive force and zero point. In addition, the three-phase electric docking assembly 34 also includes a second drive cylinder 342, a third slide rail 349, and a second spring 3453. After the hydraulic clamping mechanism 324 clamps the multi-speed electric drive assembly 7, the second drive cylinder 342 in the three-phase electric docking assembly 34 can be activated to connect the three-phase copper busbars on the multi-speed electric drive assembly 7, thereby completing the energization connection of the two stators inside the motor.

[0087] The electrical cabinet is directly fixed to base 1, facilitating overall equipment installation, debugging, and relocation. The back EMF zero-point measuring instrument 4 and the multi-speed electric drive assembly controller 5 are directly fixed to base 1 via brackets. The back EMF zero-point measuring instrument 4 requires manual connection of the signal line to the signal interface on the product before measurement. Because the multi-speed electric drive product has two motors and multiple shaft systems, and only one motor can be driven at a time when the shaft system drives the motor, shifting gears is necessary to drive the other motor. Additionally, the product's oil pump must be started for proper lubrication. Therefore, the product needs to be powered on, and the shifting motor needs to be controlled and shifted. The multi-speed electric drive assembly controller 5 uses the controller from the product on this assembly line. The PLC at this workstation can connect and control the multi-speed electric drive assembly 7 to achieve the required oil pump startup and shifting during the measurement process. The hydraulic station is directly mounted on base 1 and is used to control the clamping and releasing of the cylinder 3242 on the hydraulic clamping mechanism 324.

[0088] As can be seen from the above description, the beneficial effects of the present invention are as follows:

[0089] (1) A high-precision platform scale and its reasonable installation structure are set up, which can automatically monitor and record the weight of the product before and after testing, greatly improving the data traceability of this testing equipment. (2) An automatic oil injection and extraction component and an automatic three-phase electrical connection component are set up, which greatly improves the automation level of this testing equipment. (3) A high-strength hydraulic clamping mechanism is set up to reduce the adverse effects of product vibration on the equipment during the test. (4) A cleverly designed and highly precise rotary drive component is set up, which greatly ensures the success rate of spline shaft and docking sleeve docking and ensures the precise control of stable speed of different motors under different gear conditions. (5) The product's own controller is cleverly used as a carrier, making it possible for the equipment to control the product's oil pump motor and shift gears through PLC, which greatly simplifies the development of the equipment's software and program.

[0090] In summary, this invention provides an online back EMF zero-point detection device. Through the rational coordination and application of various devices such as a platform scale, lifting and positioning assembly, automatic oil injection and extraction docking assembly, hydraulic clamping mechanism, three-phase electrical docking assembly, rotary drive assembly, and corresponding back EMF zero-point measuring instrument, multi-speed electric drive assembly controller, hydraulic station, and lubricating oil filling machine, online measurement of the back EMF and zero point of a multi-speed electric drive assembly can be achieved. This entire device is compact, fully functional, occupies a small area, provides reliable data detection, and the detection process has no adverse effects on the product or equipment. The use of this device greatly improves the detection efficiency of back EMF zero-point detection on multi-speed electric drive assembly lines, optimizes the detection process, and significantly enhances the reliability of the detection.

[0091] Based on the description and accompanying drawings of this invention, those skilled in the art can readily manufacture or use the online back EMF zero-point detection device of this invention, and can achieve the positive effects described herein. This invention has been applied to pallets on engine assembly lines in the automotive industry.

[0092] Unless otherwise specified, in this invention, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this invention are for illustrative purposes only and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the accompanying drawings and according to the specific circumstances.

[0093] Unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An online back EMF zero-point detection device, characterized in that, The back EMF zero-point detection device includes: Base (1); The first device (2) is mounted on the base (1) and is used for positioning, lifting, automatically oiling and evacuating, and weighing the tray (6) and the multi-speed electric drive assembly (7). The first device (2) includes a platform scale (21), a lifting and positioning assembly (22), and an automatic oiling and evacuating assembly (23). The automatic oiling and evacuating assembly (23) is used for oiling and evacuating the multi-speed electric drive assembly (7) positioned on the lifting and positioning assembly (22). The automatic oiling and evacuating assembly (23) includes a fixing rod (231), which is mounted on the base (1) and evacuates from the lifting and positioning assembly (22). The fixed rod (231) is equipped with a lifting cylinder (233) and a linear guide rail (234) via a first fixed connecting seat (232). The linear guide rail (234) is slidably connected to an oil injection and extraction docking joint (236) via a first movable connecting seat (235). The lifting cylinder (233) is driven to connect with the first movable connecting seat (235). The top of the lifting and positioning assembly (22) is provided with a notch (2242) for the oil injection and extraction docking joint (236) to be lifted and connected. The automatic oil injection and extraction assembly (23) is staggered from the platform scale (21) and the lifting and positioning assembly (22) in height space. The second device (3) includes a fixed support (31), a movable clamping assembly (32), a rotary drive assembly (33), and a three-phase electrical connection assembly (34). The movable clamping assembly (32) is mounted on the base (1) via the fixed support (31) and is used to clamp the multi-speed electric drive assembly (7) on the first device (2). The rotary drive assembly (33) is mounted on the movable clamping assembly (32) and is used to connect with the spline shaft on the multi-speed electric drive assembly (7). The three-phase electrical connection assembly (34) is mounted on the movable clamping assembly (32) and is used to connect with the three-phase copper busbar on the multi-speed electric drive assembly (7). Back EMF zero point measuring instrument (4), the back EMF zero point measuring instrument (4) is installed on the base (1) and is used to detect the back EMF and zero point of the multi-stage electric drive assembly (7); A multi-speed electric drive assembly controller (5) is mounted on the base (1) and connected to the multi-speed electric drive assembly (7) to control the operation of the oil pump and the shifting operation in the multi-speed electric drive assembly (7).

2. The online back EMF zero-point detection device according to claim 1, characterized in that, The platform scale (21) is installed in the clearance groove (11) at the top of the base (1), and the position of the platform scale (21) relative to the clearance groove (11) in the height and horizontal direction is adjustable; the lifting and positioning component (22) is installed on the top of the platform scale (21), and the lifting and positioning component (22) is used to position and lift the tray (6) and the multi-speed electric drive assembly (7).

3. The online back EMF zero-point detection device according to claim 2, characterized in that, The platform scale (21) is equipped with a height adjustment structure (24) for adjusting the height position of the platform scale (21) on its bottom surface; the height adjustment structure (24) includes a clamping block (241), a screw (242) is provided through the middle of the clamping block (241), the top of the screw (242) is threaded to the bottom of the platform scale (21), a nut (244) and a disc (243) are fixed at the bottom of the screw (242) below the clamping block (241), bolt holes (246) are provided on both sides of the clamping block (241), and a first bolt (244) fixed in the clearance groove (11) is installed in the bolt holes (246). 45), the diameter of the bolt hole (246) is larger than the diameter of the first bolt (245); a horizontal adjustment structure (25) for adjusting the horizontal position of the platform scale (21) is installed in the clearance groove (11); the horizontal adjustment structure (25) includes an arc-shaped clamping block (251), the arc-shaped clamping block (251) is fixed in the clearance groove (11) by a second bolt (252), and the arc-shaped clamping block (251) has multiple first horizontal adjustment bolts (253) with different angles passing through it in the horizontal direction. The first horizontal adjustment bolts (253) can be adjusted to make tight contact with the outer circular surface of the disc (243).

4. The online back EMF zero-point detection device according to claim 2, characterized in that, The lifting and positioning assembly (22) includes a lifting and fixing frame (221), which is fixed to the platform scale (21) via a connecting base (222). A lifting plate (224) is installed above the lifting and fixing frame (221) via a telescopic sleeve (223). A lifting cylinder (225) for driving the lifting plate (224) to rise and fall is installed on the lifting and fixing frame (221). A positioning pin (2241) for positioning the pallet (6) is installed on the top surface of the lifting plate (224).

5. The online back EMF zero-point detection device according to claim 4, characterized in that, The horizontal position of the lifting and fixing frame (221) relative to the connecting base (222) is adjustable; a large hole is provided on the support plate (226) at the bottom of the lifting and fixing frame (221), and the support plate (226) is connected to the threaded hole on the connecting base (222) by a third bolt (227) passing through the large hole. The diameter of the large hole is larger than the diameter of the third bolt (227); the connecting base (222) on the outside of the support plate (226) is equipped with fixing blocks (228) in two vertical directions. A second horizontal adjusting bolt (229) is horizontally threaded through the fixing block (228), and the second horizontal adjusting bolt (229) can be adjusted to be in tight contact with the support plate (226).

6. The online back EMF zero-point detection device according to claim 1, characterized in that, The movable clamping assembly (32) includes a fixed frame (321) mounted on the top of the fixed support (31), a first movable frame (322) slidably connected to the top of the fixed frame (321), a first drive cylinder (323) for driving the first movable frame (322) to slide back and forth relative to the fixed frame (321), and a hydraulic clamping mechanism (324) mounted on the first movable frame (322) for clamping the multi-stage electric drive assembly (7); the first movable frame (322) Multiple hydraulic clamping mechanisms (324) are arranged circumferentially on the front end face of the first movable frame (322). Each hydraulic clamping mechanism (324) includes a fixed seat (3241) mounted on the front end face of the first movable frame (322), a cylinder (3242) mounted on the fixed seat (3241), and a clamping block (3243) with one end drivenly connected to the cylinder (3242). The middle part of the clamping block (3243) is rotatably connected to the fixed seat (3241) through a rotating shaft (3244) and a bearing seat (3245).

7. The online back EMF zero-point detection device according to claim 6, characterized in that, The rotary drive assembly (33) includes a second movable frame (331) slidably connected to the first movable frame (322), a first servo motor (332) for driving the second movable frame (331) to slide back and forth relative to the first movable frame (322), and a second servo motor (333) mounted on the second movable frame (331). The output end of the second servo motor (333) is connected via a telescopic assembly (334) to a docking sleeve (335) for docking with the spline shaft on the multi-speed electric drive assembly (7). The first movable frame (322) is provided with a hole for the docking sleeve (335). The telescopic assembly (334) includes a rotating shaft (3341), one end of which is connected to the output end of the second servo motor (333) via a coupling (3342), and the other end is connected to the docking sleeve (335); a limiting piece (3343) is installed in the middle of the rotating shaft (3341), and a first spring (3344) is sleeved on the rotating shaft (3341) between the limiting piece (3343) and the coupling (3342); there is a gap (3345) between the inner end of the rotating shaft (3341) and the inside of the coupling (3342).

8. The online back EMF zero-point detection device according to claim 6, characterized in that, The three-phase electrical docking assembly (34) includes a fixed bracket (341) mounted on the first movable frame (322), a second drive cylinder (342) mounted on the fixed bracket (341), a mounting plate (343) slidably connected to the bottom of the fixed bracket (341), and a docking structure (345) mounted on the mounting plate (343). The mounting plate (343) is driven connected to the output end of the second drive cylinder (342). The docking structure (345) includes a nylon connecting plate (344) mounted on the mounting plate (343), a comb-shaped guide bar (3451) mounted side by side on the nylon connecting plate (344), a connecting shaft (3452) mounted between two adjacent guide bars (3451), a second spring (3453) sleeved on the connecting shaft (3452), and a docking copper sleeve (3454) mounted on the head of the connecting shaft (3452).

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