A loader energy-saving system based on dual travel motors and its control method

Abstract

The present invention discloses an energy-saving system for a loader based on dual travel motors and a control method thereof. The system includes a first drive motor and a second drive motor. The output end of the first drive motor is connected to a first input shaft, which is connected to a first output shaft via a first transmission shaft. The first transmission shaft is provided with a first clutch, and the first output shaft is connected to the front axle. The output end of the second drive motor is connected to a second input shaft, which is connected to a second output shaft on the rear axle. A second clutch is provided between the second output shaft and the first output shaft. A vehicle controller is connected to the signals of the first drive motor, the second drive motor, the first clutch, and the second clutch. The vehicle controller controls the opening and closing of the first clutch and the second clutch according to the state of the loader. The system has a simple structure, reduces energy loss during the transmission process, and reduces energy loss caused by parasitic power by controlling the opening and closing of the first clutch and the second clutch.

Description

Technical Field

[0001] The present invention relates to the technical field of transfer machines, and in particular to a loader energy-saving system based on dual travel motors and a control method thereof. Background Art

[0002] Currently, electric loaders commonly found on the market come in two main types: dual-motor direct drive and single-motor plus gearbox drive. The dual-motor direct drive approach lacks a gearbox, with two low-speed, high-torque motors directly driving the front and rear axles. To mitigate the loss of traction that occurs when the front or rear wheels lift off, a drive shaft is installed between the two motors. This approach is simple in structure, but the use of two low-speed, high-torque motors makes the overall cost prohibitive. The single-motor plus gearbox approach, on the other hand, requires a gearbox to increase torque output, primarily because the torque of a single motor cannot meet operational requirements. This also requires ensuring high-speed travel during transitions. Consequently, the gearbox has too many gears, a complex structure, and power interruptions during shifts.

[0003] The above two electric loader driving modes also have a common problem, that is, they cannot effectively solve the energy loss problem caused by parasitic power caused by the speed difference between the front and rear wheels of the loader. Under steering and heavy load conditions, the parasitic power loss is significantly increased, thereby affecting the endurance of the entire machine. In addition, the existing electric loaders are designed with multiple intermediate shafts in the input shaft and output shaft design. This design will also lead to energy loss. Summary of the Invention

[0004] The object of the present invention is to provide an energy-saving system for a loader based on dual travel motors and a control method thereof, so as to solve the problem of high energy loss in electric loaders in the prior art.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] In a first aspect, the present invention discloses a loader energy-saving system based on dual travel motors, comprising:

[0007] A first drive motor, wherein an output end of the first drive motor is connected to a first input shaft, the first input shaft is connected to a first output shaft via a first transmission shaft, a first clutch is provided on the first transmission shaft, and the first output shaft is connected to the front axle;

[0008] A second drive motor, wherein an output end of the second drive motor is connected to a second input shaft, the second input shaft is connected to a second output shaft on the rear axle, and a second clutch is provided between the second output shaft and the first output shaft;

[0009] A vehicle controller is connected to the signals of drive motor 1, drive motor 2, clutch 1 and clutch 2. The vehicle controller controls the opening and closing of clutch 1 and clutch 2 according to the status of the loader, and controls the operation of drive motor 1 and drive motor 2.

[0010] Furthermore, the vehicle controller is also connected to the accelerator pedal signal, and the vehicle controller controls the torque of the drive motor 2 according to the opening of the accelerator pedal.

[0011] Furthermore, the first output shaft is connected to a rotation speed sensor connected to a vehicle controller signal, and the second output shaft is connected to a rotation speed sensor connected to a vehicle controller signal.

[0012] Furthermore, the peak speed of the drive motor 1 is higher than the peak speed of the drive motor 2, and the peak torque of the drive motor 1 is lower than the peak torque of the drive motor 2.

[0013] Furthermore, the clutch 1 and the clutch 2 are both hydraulic clutches.

[0014] In a second aspect, a control method for the loader energy-saving system based on dual travel motor drive according to the first aspect comprises:

[0015] Determine the state of the loader, which includes an empty state and an operating state, and the operating state includes a normal operating state;

[0016] When the loader is in an unloaded state, clutch 1 and clutch 2 are controlled to be disconnected, and drive motor 2 is controlled to operate;

[0017] When the loader is in normal operation, the controller closes clutch 1 and opens clutch 2, and controls drive motor 1 and drive motor 2 to operate.

[0018] Furthermore, determining the state of the loader includes:

[0019] The vehicle controller obtains the power information of the loader hydraulic system;

[0020] If the power of the hydraulic system is less than the set no-load threshold, the loader is in no-load state;

[0021] If the power of the hydraulic system is greater than the set no-load threshold, the loader is in working state.

[0022] Furthermore, when the loader is in the working state, the controller clutch closing includes:

[0023] determining whether the rotational speed of the first output shaft is lower than a set threshold;

[0024] controlling the clutch to close in response to a rotational speed of the first output shaft being lower than a set threshold;

[0025] In response to the rotation speed of the first output shaft being higher than a set threshold, the rotation speed of the drive motor 1 is controlled to decrease so that the rotation speed of the first output shaft is lower than the set threshold.

[0026] Furthermore, when the loader is in the working state, the controller clutch once closed further comprises:

[0027] When the clutch 1 is closed, the torque of the driving motor 1 is limited to be less than a set threshold;

[0028] When the clutch is closed, the torque of the drive motor is gradually increased according to a preset curve.

[0029] Furthermore, the operating state also includes an abnormal operating state, in which the front wheels or rear wheels of the loader are off the ground;

[0030] When the loader is in an abnormal operating state, the controller closes clutch 1 and clutch 2, and controls drive motor 1 and drive motor 2 to operate.

[0031] According to the above technical solution, the embodiments of the present invention have at least the following effects:

[0032] 1. The energy-saving system for a loader designed in this application does not have an intermediate transmission shaft between the input shaft and the first output shaft, nor does it have an intermediate transmission shaft between the second input shaft and the second output shaft, thereby reducing energy loss during transmission and, in turn, reducing energy loss during operation of the loader.

[0033] 2. The present application controls clutch 1 and clutch opening and closing through the vehicle controller. When the loader is in an unloaded state and a normal operating state, clutch 2 is in a disconnected state. This design allows the rotational speeds of the front wheels connected to the front axle and the rear wheels connected to the rear axle to be different, thereby avoiding the parasitic power problem of the loader and reducing the energy loss problem caused by the parasitic power. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the energy-saving system for a loader according to the present invention;

[0035] Figure 2 Flowchart of the control method of the present invention.

[0036] Among them: 10. Drive motor controller 1; 11. Drive motor 1; 12. First input shaft; 13. First gear set; 14. First transmission shaft; 15. Clutch 1; 16. Second gear set; 17. First output shaft; 18. Front axle; 20. Drive motor controller 2; 21. Drive motor 2; 22. Second input shaft; 23. Third gear set; 24. Rear axle; 25. Clutch 2; 3. Vehicle controller; 4. Accelerator pedal. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0038] It should be noted that, in the description of the present invention, the terms "front," "rear," "left," "right," "up," "down," "inside," and "outside" and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. These are intended solely to facilitate the description of the present invention and do not require that the present invention be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. The terms "front," "rear," "left," "right," "up," and "down" used in the description of the present invention refer to directions in the accompanying drawings, and the terms "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.

[0039] The present invention can control the on and off of clutch one and clutch two through the vehicle controller, thereby realizing the change of the vehicle's power drive mode, and switching the drive mode according to different working conditions, making full use of the motor characteristics, solving the energy loss caused by parasitic power generated under heavy working conditions, and thus improving the vehicle's endurance.

[0040] Example 1

[0041] like Figure 1 As shown, this embodiment discloses an energy-saving system for a loader based on dual travel motors, including a first drive motor 11 and a second drive motor 21. The output end of the first drive motor 11 is connected to a first input shaft 12, which is connected to a first output shaft 17 via a first transmission shaft 14. A first clutch is provided on the first transmission shaft 17, and the first output shaft 17 is connected to a front axle 18. The output end of the second drive motor 21 is connected to a second input shaft 22, which is connected to a second output shaft 24 on a rear axle 26. A second clutch 25 is provided between the second output shaft 24 and the first output shaft 17.

[0042] The vehicle controller 3 is connected to the signals of the drive motor 11, the drive motor 2 21, the clutch 15 and the clutch 2 25. The vehicle controller 3 controls the opening and closing of the clutch 15 and the clutch 2 25 according to the state of the loader, and controls the operation of the drive motor 11 and the drive motor 2 21.

[0043] The loader energy-saving system designed in this application does not set an intermediate transmission shaft between the input shaft and the first output shaft, and does not set an intermediate transmission shaft between the second input shaft and the second output shaft, thereby reducing energy loss during transmission and further reducing energy loss when the loader is working.

[0044] In this system, the first input shaft 12 and the first transmission shaft 14 are connected via the first gear set 13, the first transmission shaft 14 and the first output shaft 17 are connected via the second gear set 16, and the second input shaft 22 and the second output shaft 24 are connected via the third gear set 23.

[0045] The transmission ratio of the first gear set 13 is i1, and the transmission ratio of the second gear set 16 is i2. Therefore, the transmission ratio from the drive motor 11 to the front axle is i1*i2. The transmission ratio of the third gear set is i3. Furthermore, i1, i2, and i3 are all greater than one.

[0046] In some further embodiments, the vehicle controller is connected to the drive motor controller 10 and the drive motor controller 2 20 through a bus, and controls the outputs of the two drive motor controllers according to the signal of the accelerator pedal. The drive motor controller 10 and the drive motor controller 2 20 are respectively connected to the drive motor 11 and the drive motor 2 21 as the power source of the vehicle.

[0047] In this system, the first output shaft 17 and the second output shaft 24 are respectively equipped with speed sensors, and the vehicle controller 3 can monitor the speeds of the first output shaft 17 and the second output shaft 24 in real time through the speed sensors.

[0048] In this system, both drive motor 1 and drive motor 2 are high-speed motors. Drive motor 1 has a higher peak speed than drive motor 2, and drive motor 1 11 has a lower peak torque than drive motor 2 21. The operating states of drive motors 1 1 and 2 21 can be controlled based on the different operating conditions of the electric loader, fully utilizing the motors' high-efficiency range and improving the vehicle's endurance.

[0049] If the loader is in an unloaded transfer condition, the drive motor 2 21 is working and the drive motor 1 11 is not working. At the same time, the clutch 1 15 and the clutch 2 25 are both in the disconnected state, and the drive motor 2 21 drives the entire vehicle to move. At this time, the high-efficiency range of the drive motor 2 21 can be better utilized, thereby achieving an energy-saving effect.

[0050] When the loader is in the shoveling condition, the vehicle controller can actively control the on and off of the clutch 15 and the working state of the drive motor 11 according to the working conditions and the driving torque required by the vehicle, thereby meeting the demand for high torque drive.

[0051] During normal shoveling and transfer working conditions, the second clutch 25 is in the disconnected state. At this time, there can be a difference in the rotation speed of the front and rear wheels, thereby avoiding the parasitic power problem commonly found in loaders and reducing the energy loss problem caused by parasitic power.

[0052] When the vehicle controller detects that the difference between the rotational speed of the first output shaft 17 and the rotational speed of the second output shaft 24 is greater than the set threshold, it is determined that the vehicle has an abnormal operating phenomenon of slipping. At this time, the vehicle controller controls the clutch 25 to close to ensure that the maximum traction of the vehicle remains unchanged.

[0053] In this system, both clutch 15 and clutch 2 25 are hydraulic clutches, which reduce the impact during clutch switching, making it more stable and meeting the working conditions of the loader.

[0054] Example 2

[0055] like Figure 1 and Figure 2 As shown, based on the loader energy-saving system disclosed in the embodiment, this embodiment also discloses a control method of the energy-saving system, which includes the following steps.

[0056] Step 100: Determine the state of the loader. The loader includes an unloaded state and an operating state. The operating state includes a normal operating state and an abnormal operating state. In the abnormal operating state, the front wheels or rear wheels of the loader are off the ground.

[0057] Step 200: When the loader is in an unloaded state, the clutch 15 and clutch 2 25 are controlled to be disengaged, and the drive motor 2 21 is controlled to operate. When the loader is in a normal operating state, the clutch 15 is controlled to be engaged, clutch 2 25 is controlled to be disengaged, and the drive motor 11 and drive motor 2 21 are controlled to operate. When the loader is in an abnormal operating state, the clutch 15 and clutch 2 25 are controlled to be engaged, and the drive motor 11 and drive motor 2 21 are controlled to operate.

[0058] In a further embodiment of the present application, step 100, determining the state of the loader, can be determined in the following manner: the vehicle controller 3 can determine the vehicle state based on the power of the loader hydraulic system, which is a simple and convenient determination method.

[0059] When the hydraulic system power is less than the set no-load threshold, the vehicle is considered to be in an unloaded state. At this point, both clutch 15 and clutch 2 25 are disconnected, and drive motor 1 11 is inoperative. Drive motor 2 21 is solely responsible for driving the vehicle. The vehicle controller 3 controls the torque output of drive motor 2 21 based on the accelerator pedal position, thereby achieving normal driving under no-load conditions. Drive motor 1 11 is inoperative during this period, and the high-efficiency range of drive motor 2 21 can be better utilized during vehicle transitions, thereby achieving energy savings.

[0060] Furthermore, according to the opening of the accelerator pedal, the torque output of the drive motor 21 is controlled as follows: when driving, the vehicle controller collects the opening of the accelerator pedal and converts this throttle signal into a coefficient from 0 to 1. At the same time, the vehicle controller collects the speed information of the drive motor 2 and limits the maximum value of the requested torque of the drive motor 2 according to the discharge power limit of the battery and the external characteristic curve of the motor. The coefficient of the throttle signal is multiplied by the maximum limit of the requested torque to obtain the torque that the drive motor 2 needs to output.

[0061] When the power of the vehicle's hydraulic system is greater than the set no-load threshold, the vehicle can be considered to be in operation. At this time, the drive motor 21 working alone cannot meet the operation requirements. Therefore, the clutch 15 needs to be closed to use the drive motor 11 for torque compensation.

[0062] Drive motor 11 is a high-speed motor. Furthermore, to protect clutch 15, it is necessary to avoid engaging or disengaging clutch 15 at high speeds. Therefore, the present invention also provides a control method that determines the speed of drive motor 11 before engaging clutch 15. When the speed on first output shaft 17 is lower than a set threshold, i.e., the speed from clutch 15 to the first output shaft 17 is lower than the set threshold, clutch 15 is then controlled to engage.

[0063] Given the loader's operational characteristics, the vehicle operates at low speeds when greater traction is required. Therefore, the vehicle controller 3 must assess vehicle speed when controlling the closing of clutch 1. When the vehicle speed falls below a set threshold, clutch 15 is closed. When in neutral or reverse gear, clutch 15 is disengaged. To ensure that there is no significant speed difference between the front and rear ends of clutch 15 when clutch 15 is closed, the speed of drive motor 11 must be controlled before closing clutch 15. The speed sensor on the first output shaft 17 calculates the speed of the front end of clutch 15, and from this, the required speed of drive motor 11 is inferred, ensuring that the speed difference remains below the set threshold.

[0064] At the moment clutch 15 closes, the torque provided by drive motor 11, after two stages of transmission, is amplified several times. When the vehicle is in operation, the driver typically presses the accelerator pedal deeply, which instantly increases the vehicle's traction and may cause the vehicle to accelerate momentarily, thus affecting its operability. To address this issue of sudden power changes, the control method adds a limit on the speed at which drive motor 1's torque rises. At the moment of clutch 15 closing, drive motor 11's torque is set to a low value and then gradually increases according to a set curve until it reaches maximum torque output, avoiding the instantaneous acceleration caused by sudden power changes.

[0065] Furthermore, at the moment of engagement, the vehicle controller no longer determines the torque request for drive motor 1 based on the accelerator pedal opening. Instead, it sets the output torque of drive motor 1 to 10 Nm. After engagement, because drive motor 1's torque is relatively low, despite the torque being multiplied by both the first and second gears, the torque ultimately transmitted to output shaft 1 remains relatively low. This prevents a sudden change in vehicle torque caused by motor 1 providing a large torque instantaneously at the moment of engagement, thereby ensuring drivability and avoiding dangerous situations. After engagement is complete, the vehicle controller controls the final torque output value of drive motor 1 based on the accelerator pedal opening. The torque output is increased according to a set step size to prevent excessive acceleration, which could also affect drivability.

[0066] The vehicle controller 3 collects real-time feedback from the speed sensors on the first and second output shafts 17 and 24. Under normal circumstances, the speeds of the two output shafts are less than a set threshold. When the vehicle is heavily loaded, causing the rear wheels to lift off the ground, or when the bucket is too low during bulldozing, causing the front wheels to lift off the ground, drive motor 2 21 or drive motor 1 11 will idle, unable to transmit and compensate for their respective output torques, resulting in a decrease in vehicle traction. The clutch 2 25 of the present invention effectively addresses the power shortage. When the front or rear wheels lift off, idling occurs. When the front wheels lift off, the speed of drive motor 1 increases rapidly, while when the rear wheels lift off, the speed of drive motor 2 increases rapidly. At this point, there is a significant difference between the speeds of the first and second output shafts 17 and 24. When the difference between the two speeds exceeds a set threshold, the vehicle controller controls clutch 2 25 to close, connecting the two output shafts and enabling power transmission, preventing power shortages caused by front or rear wheel liftoff.

[0067] When clutch 25 is disengaged, there's no rigid connection between the front and rear wheels, allowing for a speed differential and effectively preventing energy loss caused by parasitic power. In this application, clutch 25 is disengaged when the transfer machine is unloaded or operating normally, effectively mitigating energy loss caused by parasitic power and achieving energy savings. Furthermore, when operating abnormally (front or rear wheels off the ground), clutch 25 is engaged, addressing the issue of power transmission failure.

[0068] It is understood from common technical knowledge that the present invention may be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the embodiments disclosed above are, in all respects, merely illustrative and not exclusive. All modifications within the scope of the present invention or equivalent to the scope of the present invention are intended to be encompassed by the present invention.

Claims

1. A loader energy-saving system based on dual travel motors, characterized in that: include: A first drive motor, wherein an output end of the first drive motor is connected to a first input shaft, the first input shaft is connected to a first output shaft via a first transmission shaft, a first clutch is provided on the first transmission shaft, and the first output shaft is connected to the front axle; A second drive motor, wherein an output end of the second drive motor is connected to a second input shaft, the second input shaft is connected to a second output shaft on the rear axle, and a second clutch is provided between the second output shaft and the first output shaft; A vehicle controller connected to drive motor 1, drive motor 2, clutch 1, and clutch 2 signals, the vehicle controller controlling the opening and closing of clutch 1 and clutch 2 according to the state of the loader, and controlling the operation of drive motor 1 and drive motor 2; When the loader is in an unloaded state, clutch 1 and clutch 2 are controlled to be disconnected, and drive motor 2 is controlled to operate; When the loader is in normal operation, the controller closes clutch 1 and opens clutch 2, and controls drive motor 1 and drive motor 2 to operate.

2. The loader energy-saving system based on dual travel motors according to claim 1 is characterized in that: The vehicle controller is also connected to the accelerator pedal signal, and the vehicle controller controls the torque of the drive motor according to the opening of the accelerator pedal.

3. The energy-saving system for a loader driven by dual travel motors according to claim 1, characterized in that: The first output shaft is connected to a rotation speed sensor connected to a vehicle controller signal, and the second output shaft is connected to a rotation speed sensor connected to a vehicle controller signal.

4. The energy-saving system for a loader driven by dual travel motors according to claim 1, characterized in that: The peak speed of the drive motor 1 is higher than the peak speed of the drive motor 2, and the peak torque of the drive motor 1 is lower than the peak torque of the drive motor 2.

5. The energy-saving system for a loader driven by dual travel motors according to claim 1, characterized in that: Both the clutch 1 and the clutch 2 are hydraulic clutches.

6. A control method for a loader energy-saving system based on dual travel motor drive according to any one of claims 1 to 5, characterized in that: include: Determine the state of the loader, which includes an empty state and an operating state, and the operating state includes a normal operating state; When the loader is in an unloaded state, clutch 1 and clutch 2 are controlled to be disconnected, and drive motor 2 is controlled to operate; When the loader is in normal operation, the controller closes clutch 1 and opens clutch 2, and controls drive motor 1 and drive motor 2 to operate.

7. The control method of the loader energy-saving system based on dual travel motor drive according to claim 6, characterized in that: Determining the state of the loader includes: The vehicle controller obtains the power information of the loader hydraulic system; If the power of the hydraulic system is less than the set no-load threshold, the loader is in no-load state; If the power of the hydraulic system is greater than the set no-load threshold, the loader is in working state.

8. The control method of the loader energy-saving system based on dual travel motor drive according to claim 6, characterized in that: When the loader is in operation, the controller clutch is closed including: determining whether the rotational speed of the first output shaft is lower than a set threshold; controlling the clutch to close in response to a rotational speed of the first output shaft being lower than a set threshold; In response to the rotation speed of the first output shaft being higher than a set threshold, the rotation speed of the drive motor 1 is controlled to decrease so that the rotation speed of the first output shaft is lower than the set threshold.

9. The control method of the loader energy-saving system based on dual travel motor drive according to claim 6, characterized in that: When the loader is in operation, the controller clutch is closed and further includes: When the clutch 1 is closed, the torque of the driving motor 1 is limited to be less than a set threshold; When the clutch is closed, the torque of the drive motor is gradually increased according to a preset curve.

10. The control method of the loader energy-saving system based on dual travel motor drive according to claim 6, characterized in that: The operating state also includes an abnormal operating state, in which the front wheels or rear wheels of the loader are off the ground; When the loader is in an abnormal operating state, the controller closes clutch 1 and clutch 2, and controls drive motor 1 and drive motor 2 to operate.

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