A dual-motor drive power transmission system, control method and loading equipment

Abstract

This application discloses a dual-motor drive power transmission system, control method, and loading equipment, belonging to the field of electric construction machinery power transmission technology. The system includes a first motor, a second motor, a drive shaft, and an overrunning clutch. The first motor is drive-connected to the drive shaft, and the second motor is disengaged from the drive shaft via the overrunning clutch. The overrunning clutch automatically locks or unlocks based on the relationship between the second motor's speed and a preset threshold. The control component induces state switching by adjusting the motor's speed and torque. This application enables on-demand coupling of dual-motor power, completely eliminating power interruption during gear shifts, optimizing energy efficiency across all operating conditions, and features a simple structure and smooth switching. It is particularly suitable for construction machinery such as loaders that require frequent start-stop operations and alternating light and heavy loads.

Description

Technical Field

[0001] This application relates to the field of electric engineering machinery power transmission technology, and in particular to a dual-motor drive power transmission system, control method and loading equipment. Background Technology

[0002] To eliminate power interruptions during gear shifts, current electric loader power systems have seen continuous simplification of gearbox structures, evolving from low-speed single motors and dual-speed gearboxes to high-speed, high-torque single motors and single-stage reducers. However, while single-motor direct-drive solutions completely eliminate interruptions, the limited high-efficiency range of the motor necessitates high power redundancy, leading to low efficiency under low load conditions and a significant increase in overall machine energy consumption. Another type of dual-motor coupling solution, while capable of power distribution, relies heavily on planetary gear sets and wet clutches, resulting in complex structures, high costs, and the risk of impact or interruption during mode switching, making it difficult to adapt to the frequent reversals and heavy load fluctuations characteristic of loaders. Summary of the Invention

[0003] The purpose of this application is to provide a dual-motor drive power transmission system, control method, and loading equipment, which solves the problem of power shifting, improves transmission efficiency, and reduces energy consumption during operation.

[0004] In a first aspect, embodiments of this application provide a dual-motor drive power transmission system, including: The motor assembly includes a first motor and a second motor; A power output assembly includes a drive shaft and an overrunning clutch, wherein a first motor is drivenly connected to the drive shaft; a second motor is disengagedly driven to the drive shaft via the overrunning clutch, and the drive shaft is used to transmit power to an external load. The overrunning clutch is configured as follows: When the output speed of the second motor is higher than the first preset threshold, it automatically switches to the locked state, so that the second motor engages with the drive shaft; When the output speed of the second motor is lower than the second preset threshold, it automatically switches to the unlocked state, which will disengage the second motor from the drive shaft; Wherein, the first preset threshold is greater than or equal to the second preset threshold.

[0005] In some embodiments, the first motor is connected to the drive shaft via a first transmission pair, and the second motor is connected to the overrunning clutch via a second transmission pair.

[0006] In some embodiments, the transmission ratio of the first transmission pair is less than the transmission ratio of the second transmission pair.

[0007] In some embodiments, both the first transmission pair and the second transmission pair are reduction gear pairs.

[0008] In some embodiments, the first transmission pair includes a first gear and a second gear that mesh with each other, the first gear being coaxially and fixedly connected to the output shaft of the first motor, and the second gear being coaxially and fixedly connected to the transmission shaft. The second transmission pair includes a third gear and a fourth gear that mesh with each other. The third gear is coaxially and fixedly connected to the output shaft of the second motor, and the fourth gear is connected to the transmission shaft through the overrunning clutch.

[0009] In some embodiments, the drive shaft is provided with a third transmission pair, and the drive shaft is connected to the load via the third transmission pair.

[0010] In some embodiments, the third transmission pair includes a fifth gear and a sixth gear that mesh with each other, the fifth gear being coaxially and fixedly connected to the transmission shaft, and the sixth gear being fixedly connected to the load.

[0011] In some embodiments, the dual-motor drive power transmission system further includes a control component, which is connected to the first motor and the second motor respectively, and is used to adjust the output speed and / or torque of the first motor and the second motor. The control component is configured to: When it is necessary to switch the overrunning clutch from the locked state to the unlocked state, the second motor is controlled to reduce its output torque and its output speed, so that the output speed of the second motor is lower than the speed of the drive shaft, so that the overrunning clutch automatically switches to the unlocked state. When it is necessary to switch the overrunning clutch from the unlocked state to the locked state, the output speed of the second motor is controlled to increase to a speed close to that of the drive shaft, so that the overrunning clutch automatically switches to the locked state, and the output torque of the second motor is gradually increased.

[0012] Secondly, embodiments of this application also provide a control method for a transmission system, applicable to the aforementioned dual-motor drive power transmission system, the control method comprising: When it is necessary to switch the overrunning clutch from the locked state to the unlocked state, the second motor is controlled to reduce its output torque and its output speed, so that the output speed of the second motor is lower than the real-time speed of the drive shaft, so that the overrunning clutch automatically switches to the unlocked state. When it is necessary to switch the overrunning clutch from the unlocked state to the locked state, the output speed of the second motor is controlled to increase to a level higher than the real-time speed of the drive shaft, so that the overrunning clutch automatically switches to the locked state, and the output torque of the second motor is gradually increased.

[0013] Thirdly, embodiments of this application also provide a loading device, including the aforementioned dual-motor drive power transmission system.

[0014] Compared with the prior art, the dual-motor drive power transmission system, control method, and loading equipment provided in this application have at least the following beneficial effects: This application sets up a first motor connected to the drive shaft and a second motor connected to the drive shaft via an overrunning clutch in a disengageable transmission manner. The overrunning clutch automatically locks when the second motor's output speed is higher than a first preset threshold and automatically unlocks when it is lower than a second preset threshold. This achieves on-demand coupling and decoupling of the dual-motor power, allowing seamless switching between dual-motor joint drive and single-motor independent drive modes without relying on any shifting mechanism. This completely eliminates power interruption during shifting, improving operational continuity and comfort. Furthermore, it enables both motors to work together and operate in the high-efficiency range under low-speed, heavy-load conditions, while only one motor drives under high-speed, light-load conditions, avoiding power redundancy and significantly reducing overall energy consumption. Simultaneously, the introduction of the overrunning clutch replaces traditional complex components such as planetary gear sets, wet clutches, or synchronizers, greatly simplifying the system structure, reducing manufacturing costs and maintenance difficulty. Moreover, the automatic switching characteristic based on speed difference ensures smooth and shock-free power engagement and disengagement, extending the service life of the transmission system. Attached Figure Description

[0015] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application or corresponding prior art. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of a dual-motor drive power transmission system in one embodiment of this application; Figure 2 This is a top view schematic diagram of a dual-motor drive power transmission system in one embodiment of this application, wherein the load is the walking mechanism of a loader; Figure 3 This is a flowchart of a control method in one embodiment of this application; The labels in the attached diagram are as follows: Motor assembly 100; first motor 110; second motor 120; first transmission pair 130; first gear 131; second gear 132; second transmission pair 140; third gear 141; fourth gear 142; Power output assembly 200; drive shaft 210; overrunning clutch 220; third transmission pair 230; fifth gear 231; sixth gear 232; Load capacity 300; walking mechanism 310. Detailed Implementation

[0016] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. The terms used in the specification are for the purpose of describing specific embodiments only and are not intended to limit the application. For example, terms such as “length”, “width”, “upper”, “lower”, “left”, “right”, “front”, “rear”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, and “outer” indicate orientations or positions based on the orientations or positions shown in the drawings and are only for ease of description and should not be construed as limiting the technical solution.

[0017] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion; the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a particular order. "A plurality of" means two or more, unless otherwise explicitly specified.

[0018] In the description, claims, and accompanying drawings of this application, when an element is referred to as "fixed to," "mounted to," "set on," or "connected to" another element, it can be directly or indirectly located on that other element. For example, when an element is referred to as "connected to" another element, it can be directly or indirectly connected to that other element. When the term "and / or" is used, it means including three parallel options; for example, "option A and / or option B" includes option A, or option B, or options that satisfy both A and B simultaneously.

[0019] Furthermore, the use of terms such as "embodiment," "implementation," and "example" in this application indicates that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. Those skilled in the art will explicitly and implicitly understand that the embodiments described in this application can be combined with other embodiments.

[0020] Currently, while single-motor direct-drive solutions eliminate power interruption during gear shifts, the motor's high-efficiency range is limited. High power redundancy is required to balance low-speed heavy-load and high-speed light-load conditions, resulting in significantly higher overall energy consumption at low loads. Traditional dual-motor coupling solutions rely heavily on planetary gear sets and wet clutches, which are structurally complex and still pose risks of impact or interruption during switching. To address these issues, this application provides a dual-motor drive power transmission system, particularly suitable for equipment such as electric loaders that require frequent start-stop operations and alternating low-speed heavy-load and high-speed light-load transfers. This aims to resolve the technical pain point of existing solutions where power continuity and energy efficiency cannot be simultaneously achieved.

[0021] like Figure 1 As shown in the figure, the dual-motor drive power transmission system provided in this application embodiment mainly includes a motor assembly 100 and a power output assembly 200. The motor assembly 100 provides driving power, and the power output assembly 200 transmits the power from the motor assembly 100 to an external load 300, such as the traveling mechanism 310 of a loader. Figure 2 As shown.

[0022] like Figure 1 As shown, the motor assembly 100 in this embodiment includes a first motor 110 and a second motor 120. The first motor 110 serves as the main drive motor, continuously outputting power under all operating conditions. The second motor 120 serves as an auxiliary drive motor, selectively connecting to the power system when high torque output is required, and working together with the first motor 110 to drive the load 300. By setting two independently controlled motors, the system can flexibly allocate power sources according to different operating conditions, providing a hardware foundation for achieving efficient operation under all conditions.

[0023] like Figure 1 As shown, the power output assembly 200 of this embodiment includes a drive shaft 210 and an overrunning clutch 220. A first motor 110 is driven by the drive shaft 210 and is used to drive the drive shaft 210 to rotate continuously. A second motor 120 is driven by the overrunning clutch 220 in a disengaging manner, meaning that the power transmission path between the second motor 120 and the drive shaft 210 can be automatically connected or disconnected by the overrunning clutch 220. The drive shaft 210, as the core component for power convergence and output, has its output end used to transmit power to an external load 300.

[0024] The overrunning clutch 220 is a mechanical element that automatically engages or disengages based on the relative rotational speeds of the driving and driven components. In this application, the overrunning clutch 220 is configured as follows: When the output speed of the second motor 120 is higher than the first preset threshold, the overrunning clutch 220 automatically switches to the locked state, so that the second motor 120 engages with the drive shaft 210. At this time, the power of the second motor 120 is transmitted to the drive shaft 210 through the overrunning clutch 220, and the power of the first motor 110 is combined at the drive shaft 210 to jointly drive the load 300.

[0025] When the output speed of the second motor 120 is lower than the second preset threshold, the overrunning clutch 220 automatically switches to the unlocked state, disengaging the second motor 120 from the drive shaft 210. At this time, the power transmission path of the second motor 120 is cut off, and the drive shaft 210 is driven solely by the first motor 110.

[0026] It should be noted that the first and second preset thresholds mentioned above are not fixed absolute values, but are essentially dynamic, changing with the real-time rotational speed of the drive shaft 210. Specifically, the first preset threshold is the real-time rotational speed of the drive shaft 210 (or a slightly higher value), meaning that when the output speed of the second motor 120 exceeds the real-time rotational speed of the drive shaft 210, the overrunning clutch 220 locks; the second preset threshold is the real-time rotational speed of the drive shaft 210 (or a slightly lower value), meaning that when the output speed of the second motor 120 is lower than the real-time rotational speed of the drive shaft 210, the overrunning clutch 220 unlocks. In other words, the reference point for the overrunning clutch 220 to determine locking or unlocking is always the current rotational speed of the drive shaft 210, and the switching condition is essentially the relative magnitude relationship between the output speed of the second motor 120 and the real-time rotational speed of the drive shaft 210.

[0027] The switching condition of the overrunning clutch 220 uses the real-time rotational speed of the drive shaft 210 as a dynamic reference, ensuring that the switching of the overrunning clutch 220 always matches the actual operating state of the drive shaft 210. The system has strong adaptive capability and does not require pre-calibration of fixed switching speed values ​​for different vehicle speeds or operating conditions. The aforementioned mechanical automatic response characteristics of the overrunning clutch 220 enable the system to achieve on-demand coupling and decoupling of dual-motor power without the need for any shifting mechanism (such as a sliding sleeve, synchronizer, or wet clutch). The entire switching process is automatically completed by the overrunning clutch 220 based on the speed difference, without the need for external control commands to trigger the switching action, resulting in rapid response and no power interruption.

[0028] Furthermore, such as Figure 1 As shown, the first motor 110 is connected to the drive shaft 210 via the first transmission pair 130, and the second motor 120 is connected to the overrunning clutch 220 via the second transmission pair 140. The transmission pairs are used to reduce speed and increase torque between the motor output shaft and the drive shaft 210, so that the high-speed, low-torque power output by the motor is converted into low-speed, high-torque power suitable for the load 300.

[0029] In this embodiment, both the first transmission pair 130 and the second transmission pair 140 are reduction gear pairs, and the transmission ratio of the first transmission pair 130 is smaller than that of the second transmission pair 140. This difference in transmission ratio creates conditions for the automatic switching of the overrunning clutch 220: because the reduction ratio of the second transmission pair 140 is larger, at the same motor speed, the output speed of the second motor 120 after being reduced by the second transmission pair 140 is lower than the output speed of the first motor 110 after being reduced by the first transmission pair 130. This means that when the second motor 120 needs to be disengaged, only the speed of the second motor 120 needs to be reduced to automatically unlock the overrunning clutch 220; and when the second motor 120 needs to be engaged, only the speed of the second motor 120 needs to be increased to exceed the speed of the transmission shaft 210 to automatically lock the overrunning clutch 220.

[0030] Specifically, such as Figure 1 As shown, the first transmission pair 130 includes a first gear 131 and a second gear 132 that mesh with each other. The first gear 131 is coaxially and fixedly connected to the output shaft of the first motor 110 and rotates synchronously with the output shaft of the first motor 110; the second gear 132 is coaxially and fixedly connected to the transmission shaft 210. The power of the first motor 110 is transmitted to the second gear 132 through the meshing of the first gear 131, and then transmitted to the transmission shaft 210 by the second gear 132. By reasonably selecting the gear ratio of the first gear 131 and the second gear 132, a first-stage speed reduction and torque increase can be achieved between the first motor 110 and the transmission shaft 210.

[0031] like Figure 1 As shown, the second transmission pair 140 includes a third gear 141 and a fourth gear 142 that mesh with each other. The third gear 141 is coaxially and fixedly connected to the output shaft of the second motor 120 and rotates synchronously with the output shaft of the second motor 120; the fourth gear 142 is connected to the transmission shaft 210 through an overrunning clutch 220. The power of the second motor 120 is transmitted to the fourth gear 142 through the engagement of the third gear 141. When the overrunning clutch 220 is in the locked state, the power of the fourth gear 142 is transmitted to the transmission shaft 210 through the overrunning clutch 220; when the overrunning clutch 220 is in the unlocked state, the power transmission between the fourth gear 142 and the transmission shaft 210 is cut off, and the second motor 120 is disengaged from the transmission shaft 210.

[0032] like Figure 1As shown, the drive shaft 210 is connected to the load 300 via a third transmission pair 230. In this embodiment, the third transmission pair 230 is also a reduction gear pair, which includes a fifth gear 231 and a sixth gear 232 meshing with each other. The fifth gear 231 is coaxially and fixedly connected to the drive shaft 210 and rotates synchronously with the drive shaft 210; the sixth gear 232 is used to coaxially and fixedly connect to the input shaft of the load 300 (such as the input shaft of a loader rear axle or wheel-side reducer). The power gathered on the drive shaft 210 is transmitted to the sixth gear 232 through the meshing of the fifth gear 231, and then output to the load 300 by the sixth gear 232, realizing the final stage of reduction and torque increase.

[0033] like Figure 1 As shown, this application achieves a reasonable reduction ratio distribution between the motor output end and the load 300 through the cooperation of the above three-stage transmission pairs (the first motor 110 is transmitted through the first transmission pair 130, the second motor 120 is transmitted through the second transmission pair 140, and after merging, it is output through the third transmission pair 230), ensuring that sufficient output torque can be provided under different working conditions.

[0034] It should be noted that in some other embodiments, the first transmission pair 130, the second transmission pair 140 and the third transmission pair 230 are not limited to gear pairs. They can also be synchronous belt transmission pairs, chain transmission pairs or other transmission forms with speed reduction function, depending on the specific arrangement requirements, as long as they can achieve speed reduction and torque increase transmission between the motor output end and the transmission shaft 210.

[0035] Furthermore, in some embodiments, the types of the first motor 110 and the second motor 120 can be selected according to the actual power level and the overall vehicle layout space, such as using a permanent magnet synchronous motor, an AC asynchronous motor or other types of motors, and this application does not make specific limitations in this regard.

[0036] Furthermore, the dual-motor drive power transmission system also includes a control component (not shown). The control component is electrically connected to the first motor 110 and the second motor 120, respectively, and is used to adjust the output speed and / or torque of the first motor 110 and the second motor 120. By actively adjusting the speed and torque of the second motor 120, the control component changes the relative magnitude between the output speed of the second motor 120 and the real-time speed of the drive shaft 210, thereby inducing the overrunning clutch 220 to automatically switch between a locked state and an unlocked state.

[0037] The control component in this application embodiment can be an independent vehicle controller, a control module integrated into the motor controller, or a combination of multiple distributed control units. Regardless of the physical form, its function is to be electrically connected to the first motor 110 and the second motor 120 respectively (via CAN bus or hard-wired signal connection) to send speed commands and / or torque commands to the motor controllers of the first motor 110 and the second motor 120, thereby realizing independent adjustment of the output speed and / or output torque of the first motor 110 and the second motor 120.

[0038] Specifically, the control component is configured to execute the following control policies: When it is necessary to switch the overrunning clutch 220 from the locked state to the unlocked state (e.g., from low-speed heavy-load operation to high-speed light-load operation), the control component controls the second motor 120 to reduce its output torque and then gradually reduce its output speed, so that the output speed of the second motor 120 is lower than the real-time speed of the drive shaft 210. At this time, the output speed of the second motor 120 is lower than the second preset threshold (which is essentially the real-time speed of the drive shaft 210). Based on its mechanical characteristics, the overrunning clutch 220 automatically switches to the unlocked state, disengaging the second motor 120 from the drive shaft 210. The control sequence of reducing torque first and then reducing speed ensures that no impact load is generated at the moment the overrunning clutch 220 unlocks, because the pre-unloading of torque ensures that there is no separation under load during disengagement, and the disengagement process is smooth and stable.

[0039] When it is necessary to switch the overrunning clutch 220 from the unlocked state to the locked state (e.g., from high-speed light-load transfer to low-speed heavy-load operation), the control component first controls the output speed of the second motor 120 to increase, making the output speed of the second motor 120 higher than the real-time speed of the drive shaft 210. After the overrunning clutch 220 automatically switches to the locked state, the output torque of the second motor 120 is gradually increased. When the output speed of the second motor 120 increases to exceed a first preset threshold (which is essentially the real-time speed of the drive shaft 210), the overrunning clutch 220 automatically switches to the locked state based on its mechanical characteristics, engaging the second motor 120 with the drive shaft 210. Gradually applying torque after locking avoids the impact load caused by sudden torque changes at the moment of locking, ensuring the smoothness of the engagement process.

[0040] Through the aforementioned control strategy, the control component and the overrunning clutch 220 work in concert: the control component adjusts the speed of the second motor 120 to change the speed difference between it and the drive shaft 210, causing it to cross a first preset threshold or a second preset threshold; the overrunning clutch 220, based on its own mechanical characteristics, automatically locks or unlocks when the speed difference exceeds the corresponding threshold. This combination enables on-demand switching of power modes while ensuring a smooth and shock-free switching process.

[0041] The working principle of the system in this application embodiment will be explained in detail below with reference to the typical working cycle of a loader.

[0042] Low-speed heavy-load mode: When the loader is starting, loading, or operating under low-speed heavy load, the machine requires high torque and has a high load rate. At this time, the control unit controls the second motor 120 to increase its output speed, raising it above the real-time speed of the drive shaft 210, i.e., reaching and exceeding the first preset threshold. At this point, the overrunning clutch 220 automatically switches to the locked state, engaging the second motor 120 with the drive shaft 210. In this state, the power of the first motor 110 is transmitted to the drive shaft 210 via the first transmission pair 130, and the power of the second motor 120 is transmitted to the drive shaft 210 via the second transmission pair 140 and the overrunning clutch 220. The two power sources converge at the drive shaft 210 and then jointly drive the load 300 via the third transmission pair 230.

[0043] Since both motors share the 300kW load, each motor maintains its own high-efficiency load range, avoiding the low-load inefficiency problem caused by having to use a high-power motor to cover high torque requirements in a single-motor solution. Overall energy consumption is effectively controlled. Meanwhile, the overrunning clutch 220 lock-up process is automatically triggered by the speed difference, requiring no manual intervention or external shift signals. The transmission path remains continuous throughout the entire power convergence process, with no interruption in power during shifting.

[0044] High-speed light-load mode: When the loader completes its loading operation and enters a high-speed transfer or light-load driving state, the overall power demand and load rate are low, requiring only a single motor to meet the drive requirements. At this time, the control unit first controls the second motor 120 to reduce its output torque, and then gradually reduces its output speed until the output speed of the second motor 120 is lower than the real-time speed of the drive shaft 210, i.e., lower than the second preset threshold. At this point, the overrunning clutch 220 automatically switches to the unlocked state, the second motor 120 disengages from the drive shaft 210, and the second motor 120 stops working and no longer outputs power to the drive shaft 210. At this time, only the first motor 110 drives the load 300 via the first transmission pair 130 and the third transmission pair 230.

[0045] Since the second motor 120 has completely exited the power transmission path, the system only needs to keep the first motor 110 operating in the high-efficiency range. The second motor 120 has no power redundancy loss, thereby further reducing the overall energy consumption. At the same time, after the overrunning clutch 220 is unlocked, the second motor 120 is completely disengaged from the drive shaft 210. The second motor 120 no longer passively rotates with the drive shaft 210, reducing unnecessary rotational inertia and mechanical losses, which helps to further improve system efficiency.

[0046] During the switching process of locking and unlocking the overrunning clutch 220, the switching action is automatically completed by the overrunning clutch 220 based on the relationship between the output speed of the second motor 120 and the first preset threshold or the second preset threshold. These two thresholds are essentially the real-time speed of the drive shaft 210. Therefore, the switching is always matched with the actual operating state of the drive shaft. With the control strategy of adjusting the speed first and then the torque, when unlocking, the torque is first unloaded and then the speed is reduced to be lower than the second preset threshold. When locking, the speed is first increased to be higher than the first preset threshold and then the torque is applied. This ensures that the switching process is smooth and shock-free, effectively avoiding the jerking, impact load and power interruption phenomena commonly found in traditional gear shifting mechanisms. This improves the driver's operating comfort and extends the service life of transmission system components.

[0047] In some embodiments, the first preset threshold and the second preset threshold can be calibrated according to specific operating conditions and motor characteristics. The first preset threshold is usually greater than or equal to the second preset threshold to avoid frequent switching of the overrunning clutch 220 near the threshold and to ensure the stability of the system operation. Since both are essentially the real-time rotational speed of the drive shaft 210, in actual engineering applications, the first preset threshold can be set to 100% to 105% of the real-time rotational speed of the drive shaft 210 (i.e., it needs to exceed the current speed by a certain margin before locking), and the second preset threshold can be set to 95% to 100% of the real-time rotational speed of the drive shaft 210 (i.e., it needs to be lower than the current speed by a certain margin before unlocking). The specific values ​​can be adjusted according to the specific model and response characteristics of the overrunning clutch 220, and this application does not impose specific limitations on this.

[0048] The dual-motor drive power transmission system of this application embodiment has achieved significant technical effects in terms of completely eliminating power interruption during gear shifting, improving transmission efficiency under all working conditions, simplifying system structure, and reducing manufacturing costs through the above-mentioned structural configuration and control strategy. It is especially suitable for engineering machinery equipment such as electric loaders that need to frequently alternate between low-speed heavy-load operations and high-speed light-load transfers.

[0049] This application also provides a control method for a transmission system, applicable to the dual-motor drive power transmission systems of the above embodiments. This control method is based on the automatic response characteristics of the overrunning clutch 220 due to speed difference. It actively adjusts the output speed and torque of the second motor 120 through control components to change the relative relationship between the output speed of the second motor 120 and the real-time speed of the drive shaft 210, thereby inducing the overrunning clutch 220 to automatically switch between locked and unlocked states, achieving on-demand switching of the dual-motor power mode. The following is combined with… Figure 3 The flowchart shown below provides a detailed explanation of the specific steps of the control method in this application.

[0050] Step S100: When it is necessary to enter the low-speed heavy-load working condition, control the output speed of the second motor 120 to increase to a level higher than the first preset threshold, so that the overrunning clutch 220 automatically switches to the locked state, and gradually increases the output torque of the second motor 120, so that the first motor 110 and the second motor 120 jointly drive the transmission shaft 210.

[0051] When the loader needs to enter a low-speed, heavy-load operating condition, such as when starting, loading, or climbing a heavy-load hill, the system needs to switch from a single-motor drive mode to a dual-motor drive mode to provide sufficient output torque and ensure that both motors operate in their high-efficiency range.

[0052] The control component sends a speed increase command to the second motor 120, gradually increasing the speed of the second motor 120. During this process, the power of the second motor 120 is transmitted to the overrunning clutch 220 via the second transmission pair 140. When the output speed of the second motor 120 increases to exceed the first preset threshold (which is essentially the real-time speed of the transmission shaft 210, requiring the second motor 120 to reach and exceed the current speed of the transmission shaft 210), the speed of the driving component of the overrunning clutch 220 is higher than the speed of the driven component. Based on its mechanical characteristics, the overrunning clutch 220 automatically switches to the locked state, and the second motor 120 automatically engages with the transmission shaft 210.

[0053] It should be noted that the first preset threshold here is not a fixed speed value, but rather a dynamic value that changes with the real-time speed of the drive shaft 210. It is set to a dynamic value that is slightly higher than the real-time speed of the drive shaft 210 (e.g., 100% to 105% of the real-time speed of the drive shaft 210) to ensure that the overrunning clutch 220 has a clear speed difference at the moment of locking, thus avoiding frequent switching near the threshold.

[0054] After confirming that the overrunning clutch 220 has switched to the locked state, the control component sends a torque loading command to the second motor 120, gradually increasing the output torque of the second motor 120 until it smoothly rises to the target torque value. During this process, the first motor 110 remains continuously operating, and its power is transmitted to the drive shaft 210 via the first transmission pair 130; the power of the second motor 120 is transmitted to the drive shaft 210 via the second transmission pair 140 and the overrunning clutch 220. The two power sources converge at the drive shaft 210 and jointly drive the load 300 via the third transmission pair 230.

[0055] Once the second motor has applied 120 Nm of torque, the system enters a stable dual-motor drive state. At this time, the two motors jointly bear a load of 300 Nm of power, and the load rate of each motor is maintained within its respective high-efficiency range, thereby optimizing the overall energy consumption while ensuring high torque output.

[0056] In this step, the control sequence of increasing speed first and then increasing torque is crucial. If a large torque is applied at the moment of lock-up, an impact load will be generated, which may damage the transmission system components. This application ensures the smoothness of the lock-up process and avoids the generation of impact loads by first establishing a speed difference to smoothly engage the overrunning clutch 220 and then gradually applying torque. At the same time, since the overrunning clutch 220 is automatically triggered to lock up by the speed difference, no shifting mechanism is required throughout the process, and the power transmission path remains continuous without any power interruption.

[0057] Step S200: When it is necessary to enter the high-speed light-load working condition, control the second motor 120 to reduce the output torque and reduce its output speed to below the second preset threshold, so that the overrunning clutch 220 automatically switches to the unlocked state, so that the second motor 120 is disengaged from the drive shaft 210, and the first motor 110 drives the drive shaft 210 alone.

[0058] When the loader needs to enter a high-speed, light-load operating condition, such as when it enters a transfer or fast-moving state after completing a loading operation, the system needs to switch from the dual-motor common drive mode to the single-motor independent drive mode to avoid power redundancy loss caused by the inefficient operation of the second motor 120 under low-load conditions.

[0059] The control unit sends a torque unloading command to the second motor 120, gradually reducing the output torque of the second motor 120 until its torque value drops to near zero or to a preset safe unloading value. The purpose of this step is to pre-unload the load of the second motor 120 before the overrunning clutch 220 disengages, avoiding the impact and abnormal wear caused by disengagement under load.

[0060] After the torque unloading of the second motor 120 is completed, the control component sends a speed reduction command to the second motor 120, gradually reducing its output speed. When the output speed of the second motor 120 decreases below a second preset threshold, which is essentially the real-time speed of the drive shaft 210, the second motor 120's speed must be lower than the current drive shaft 210's speed. The driving component of the overrunning clutch 220 must also have a lower speed than the driven component. Based on its mechanical characteristics, the overrunning clutch 220 automatically switches to the unlocked state, and the second motor 120 automatically disengages from the drive shaft 210. It should be noted that this second preset threshold is not a fixed speed value, but rather dynamically changes with the real-time speed of the drive shaft 210. It is set to a dynamic value slightly lower than the real-time speed of the drive shaft 210 (e.g., 95%~100% of the real-time speed of the drive shaft 210) to ensure that the overrunning clutch 220 has a clear speed difference at the moment of unlocking, avoiding frequent switching near the threshold.

[0061] The second motor 120 disengages from the drive shaft 210, and the first motor 110 drives the drive shaft 210 alone. When the overrunning clutch 220 switches to the unlocked state, the power transmission path of the second motor 120 is completely cut off, the second motor 120 stops working, and no longer outputs power to the drive shaft 210. At this time, only the first motor 110 drives the load 300 through the first transmission pair 130 and the third transmission pair 230. The system enters a stable single-motor drive state.

[0062] In this step, the control sequence of first reducing torque and then reducing speed is crucial. If the speed of the second motor 120 is reduced directly while the overrunning clutch 220 is still locked, the second motor 120 may be dragged backward by the drive shaft 210 under load, resulting in impact and additional energy loss. This application ensures the smoothness of the disengagement process by first unloading the load of the second motor 120 and then gradually reducing the speed to allow the overrunning clutch 220 to disengage smoothly, avoiding impact loads and slippage losses. At the same time, since the overrunning clutch 220 is automatically triggered to unlock by the speed difference, the entire switching process does not require a gear shifting mechanism, and the power transmission path remains continuous without any power interruption.

[0063] The control method for the transmission system provided in this application embodiment, in conjunction with the above-mentioned dual-motor drive power transmission system, has at least the following beneficial effects: The control components only need to adjust the output speed and torque of the second motor 120 to achieve on-demand switching of the power mode, eliminating the need for complex timing control and synchronization control algorithms, thus reducing the development difficulty and hardware cost of the control system. Through a control strategy of adjusting speed first and then torque, the speed is increased before the torque is increased during locking, and the torque is decreased before the speed is decreased during unlocking, ensuring that the overrunning clutch 220 experiences no impact load during switching, avoiding premature damage to transmission system components and extending the system's service life. The locking and unlocking of the overrunning clutch 220 are automatically triggered by the speed difference. During the switching process, the drive shaft 210 remains rotating, ensuring a continuous power transmission path and eliminating the power interruption phenomenon of traditional shifting mechanisms. This significantly improves the loader's operational continuity and user comfort. By automatically switching between single / dual motor drive modes under different working conditions, the motor always operates in its high-efficiency range, avoiding the inefficient operation of a single-motor solution under low-load conditions due to power redundancy. This significantly reduces overall energy consumption and achieves efficient operation under all working conditions.

[0064] This application also provides a loading device, including the dual-motor drive power transmission system of the above embodiments.

[0065] The loading equipment provided in this application is not limited to loaders, but can also be other types of construction machinery or electric vehicles such as excavators, bulldozers, mining trucks, forklifts, and tractors. As long as their power systems need to frequently switch between different working conditions such as low-speed heavy load and high-speed light load, the technical solution of this application can be adopted to achieve a balance between power continuity and energy efficiency.

[0066] The above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A dual-motor drive power transmission system, characterized in that, include: The motor assembly includes a first motor and a second motor; The power output assembly includes a drive shaft and an overrunning clutch, wherein the first motor is drive-connected to the drive shaft; The second motor is connected to the drive shaft in a disengaging manner via the overrunning clutch, and the drive shaft is used to transmit power to an external load; The overrunning clutch is configured as follows: When the output speed of the second motor is higher than the first preset threshold, it automatically switches to the locked state, so that the second motor engages with the transmission shaft; When the output speed of the second motor is lower than the second preset threshold, it automatically switches to the unlocked state, disengaging the second motor from the drive shaft; Wherein, the first preset threshold is greater than or equal to the second preset threshold.

2. The dual-motor drive power transmission system according to claim 1, characterized in that, The first motor is connected to the drive shaft via a first transmission pair, and the second motor is connected to the overrunning clutch via a second transmission pair.

3. The dual-motor drive power transmission system according to claim 2, characterized in that, The transmission ratio of the first transmission pair is less than that of the second transmission pair.

4. The dual-motor drive power transmission system according to claim 2, characterized in that, Both the first transmission pair and the second transmission pair are reduction gear pairs.

5. The dual-motor drive power transmission system according to claim 4, characterized in that, The first transmission pair includes a first gear and a second gear that mesh with each other. The first gear is coaxially and fixedly connected to the output shaft of the first motor, and the second gear is coaxially and fixedly connected to the transmission shaft. The second transmission pair includes a third gear and a fourth gear that mesh with each other. The third gear is coaxially and fixedly connected to the output shaft of the second motor, and the fourth gear is connected to the transmission shaft through the overrunning clutch.

6. The dual-motor drive power transmission system according to claim 1, characterized in that, The drive shaft is provided with a third transmission pair, and the drive shaft is connected to the load through the third transmission pair.

7. The dual-motor drive power transmission system according to claim 6, characterized in that, The third transmission pair includes a fifth gear and a sixth gear that mesh with each other. The fifth gear is coaxially and fixedly connected to the transmission shaft, and the sixth gear is used to be fixedly connected to the load.

8. The dual-motor drive power transmission system according to any one of claims 1 to 7, characterized in that, The dual-motor drive power transmission system further includes a control component, which is connected to the first motor and the second motor respectively, and is used to adjust the output speed and / or torque of the first motor and the second motor. The control component is configured to: When it is necessary to switch the overrunning clutch from the locked state to the unlocked state, the second motor is controlled to reduce its output torque and its output speed, so that the output speed of the second motor is lower than the real-time speed of the drive shaft, so that the overrunning clutch automatically switches to the unlocked state. When it is necessary to switch the overrunning clutch from the unlocked state to the locked state, the output speed of the second motor is controlled to increase to a level higher than the real-time speed of the drive shaft, so that the overrunning clutch automatically switches to the locked state, and the output torque of the second motor is gradually increased.

9. A control method for a transmission system, characterized in that, The control method, applicable to the dual-motor drive power transmission system as described in any one of claims 1 to 8, comprises: When it is necessary to enter a low-speed heavy-load working condition, the output speed of the second motor is controlled to increase to a level higher than the first preset threshold, so that the overrunning clutch automatically switches to the locked state, and the output torque of the second motor is gradually increased, so that the first motor and the second motor jointly drive the transmission shaft; When it is necessary to enter a high-speed, light-load operating condition, the second motor is controlled to reduce its output torque and its output speed to below the second preset threshold, so that the overrunning clutch automatically switches to the unlocked state, disengaging the second motor from the drive shaft, and the first motor drives the drive shaft alone.

10. A loading device, characterized in that, Includes the dual-motor drive power transmission system as described in any one of claims 1 to 8.

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