Control Method and Device for Lubrication Flow Rate

Abstract

The present application discloses a method and device for controlling lubrication flow rate. Among them, the vehicle includes an electric drive system, and the electric drive system includes a planetary gear set and an oil pump. In the planetary gear set, the planetary gears are supported on the pin shafts of the planet carrier through needle bearings. The control method includes: determining the current load value of the needle bearings of the planetary gear set according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed; determining the target lubrication flow rate of the needle bearings according to the current load value and a preset relationship curve, where the preset relationship curve is used to characterize the corresponding relationship between the load value of the needle bearings and the lubrication flow rate, or is used to characterize the corresponding relationship between the load value of the needle bearings and the oil pump speed. Through the technical solution provided by the present application, by accurately quantifying the lubrication flow rate control according to the current load value borne by the needle bearings of the planetary gear set, not only the reliability of the needle bearings is ensured, but also the power consumption of the vehicle is reduced.

Description

Technical Field

[0001] This application belongs to the technical field of vehicle control, and particularly relates to a control method and device for lubrication flow rate. Background Art

[0002] In hybrid electric drive and pure electric drive vehicles, planetary gear sets are often used to achieve speed ratio conversion between the engine and the generator, as well as speed ratio conversion between the motor and the wheel hub, so as to ensure that the generator is driven by the engine to operate in the high-efficiency area with a relatively high speed, and to achieve speed reduction and torque increase from the motor to the wheel hub. Compared with parallel distributed gear shafts, the planetary gear set greatly reduces the spatial size of the gear shaft. The needle roller bearings that support the planetary gears inside the planetary gear set are sensitive to the lubrication flow rate and are the most critical parts in the lubrication of the entire electric drive system.

[0003] How to control the lubrication flow rate to ensure the reliability of the needle roller bearings of the planetary gear set is an urgent problem to be solved. Summary of the Invention

[0004] Embodiments of the present application provide a control method and device for lubrication flow rate, which can at least to a certain extent ensure the reliability of the needle roller bearings of the planetary gear set.

[0005] Other features and advantages of the present application will become apparent through the following detailed description, or will be learned in part through the practice of the present application.

[0006] According to a first aspect of the embodiments of the present application, a control method for lubrication flow rate is provided, which is applied to a vehicle. The vehicle includes an electric drive system, and the electric drive system includes a planetary gear set and an oil pump. In the planetary gear set, the planetary gears are supported on the pins of the planet carrier by needle roller bearings. The control method includes:

[0007] Determine the current load value of the needle roller bearings of the planetary gear set according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed;

[0008] Determine the target lubrication flow rate of the needle roller bearings according to the current load value and a preset relationship curve. The preset relationship curve is used to represent the corresponding relationship between the load value of the needle roller bearings and the lubrication flow rate, or is used to represent the corresponding relationship between the load value of the needle roller bearings and the oil pump speed.

[0009] In some embodiments of the present application, based on the foregoing solution, the electric drive system further includes an engine and a generator. The planet carrier is connected to the engine, and the sun gear is connected to the generator. The step of determining the current load value of the needle roller bearings of the planetary gear set according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed includes:

[0010] Take the current engine torque as the current carrier torque, take the current engine speed as the current carrier speed, take the current generator torque as the current sun gear torque, and take the current generator speed as the current sun gear speed;

[0011] Determine the current load value according to the current engine torque, the current engine speed, the current generator torque, the current generator speed, the number of teeth of the sun gear, the number of teeth of the ring gear, the normal pressure angle of the planetary gear, the helix angle of the planetary gear, and the pitch diameter of the planetary gear.

[0012] In some embodiments of the present application, based on the foregoing solution, the current load value is calculated according to the following formula:

[0013]

[0014] Where X is the current load value, T e is the current engine torque, T s is the current generator torque, Z1 is the number of teeth of the sun gear, Z2 is the number of teeth of the ring gear, V e is the current engine speed, V s is the current generator speed, α is the normal pressure angle, β is the helix angle, and d is the pitch diameter.

[0015] In some embodiments of the present application, based on the foregoing solution, the electric drive system further includes an engine and a generator. The carrier is connected to the engine, and the sun gear is connected to the generator. Determining the current load value of the needle roller bearing of the planetary gear set according to the current carrier torque, the current carrier speed, the current sun gear torque, and the current sun gear speed includes:

[0016] Take the current engine torque as the current carrier torque, take the current engine speed as the current carrier speed, take the current generator torque as the current sun gear torque, and take the current generator speed as the current sun gear speed;

[0017] Determine the speed ratio coefficient according to the number of teeth of the sun gear and the number of teeth of the ring gear;

[0018] Determine the current load value according to the current engine torque, the current engine speed, the current generator torque, the current generator speed, and the speed ratio coefficient.

[0019] In some embodiments of the present application, based on the foregoing solution, the current load value is calculated according to the following formula:

[0020] X = |(T e-KT s )(V e -V s )|;

[0021] K = -(Z2 / Z1 + 1);

[0022] Wherein, X is the current load value, T e is the current engine torque, T s is the current generator torque, K is the speed ratio coefficient, V e is the current engine speed, V s is the current generator speed, Z1 is the number of teeth of the sun gear, and Z2 is the number of teeth of the ring gear.

[0023] In some embodiments of the present application, based on the foregoing solution, the electric drive system further includes a motor, the planet carrier is connected to the wheel end output shaft, the sun gear is connected to the motor, and determining the current load value of the needle bearing of the planetary gear set according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed includes:

[0024] Taking the current wheel end output shaft torque as the current planet carrier torque, taking the current wheel end output shaft speed as the current planet carrier speed, taking the current motor torque as the current sun gear torque, and taking the current motor speed as the current sun gear speed;

[0025] Determining the current load value of the needle bearing of the planetary gear set according to the current wheel end output shaft torque, the current wheel end output shaft speed, the current motor torque, and the current motor speed.

[0026] In some embodiments of the present application, based on the foregoing solution, determining the target lubrication flow rate of the needle bearing according to the current load value and the preset relationship curve includes:

[0027] When the preset relationship curve is used to represent the corresponding relationship between the load value and the lubrication flow rate of the needle bearing, determining the lubrication flow rate corresponding to the current load value from the preset relationship curve, and taking the determined lubrication flow rate as the target lubrication flow rate of the needle bearing;

[0028] When the preset relationship curve is used to represent the corresponding relationship between the load value and the oil pump speed of the needle bearing, determining the oil pump speed corresponding to the current load value from the preset relationship curve, and obtaining the target lubrication flow rate of the needle bearing according to the determined oil pump speed.

[0029] In some embodiments of the present application, based on the foregoing solution, the control method further includes:

[0030] Perform a reliability test on the electric drive system to obtain multiple load values of the needle bearings of the planetary gear set and the lubrication flow rate or the oil pump speed corresponding to each load value under the condition of passing the reliability test;

[0031] Fit all the load values and the lubrication flow rate corresponding to the load values, or fit all the load values and the oil pump speed corresponding to the load values to obtain the preset relationship curve.

[0032] In some embodiments of the present application, based on the foregoing solution, the control method further includes:

[0033] Control the target speed of the oil pump according to the target lubrication flow rate.

[0034] According to the second aspect of the embodiments of the present application, there is provided a control device for lubrication flow rate, including a processor and a memory. The memory stores computer program instructions that can be executed by the processor. When the processor executes the computer program instructions, the steps of the method described in any one of the above first aspects are implemented.

[0035] In the present application, the current load value of the needle bearing of the planetary gear set is determined according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed; according to the current load value and the preset relationship curve, the target lubrication flow rate of the needle bearing is determined. The preset relationship curve is used to characterize the corresponding relationship between the load value of the needle bearing and the lubrication flow rate, or to characterize the corresponding relationship between the load value of the needle bearing and the oil pump speed. Through the technical solution provided by the present application, precise quantitative control of the lubrication flow rate is performed according to the current load value borne by the needle bearing of the planetary gear set, which not only ensures the reliability of the needle bearing but also reduces the power consumption of the vehicle.

[0036] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application. Obviously, the following drawings in the description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0038] Figure 1 A schematic flowchart of a control method for lubrication flow rate in an embodiment is shown;

[0039] Figure 2 The structural schematic diagram of a planetary gear set in an embodiment is shown;

[0040] Figure 3 The schematic diagram of a preset relationship curve in an embodiment is shown;

[0041] Figure 4 The flowchart of the control method of lubrication flow rate in another embodiment is shown;

[0042] Figure 5 shown is Figure 4 the schematic diagram of the data flow in

[0043] Figure 6 The block diagram of the control device of lubrication flow rate in an embodiment is shown;

[0044] Figure 7 The structural schematic diagram of the control device of lubrication flow rate in an embodiment is shown. Detailed implementation manners

[0045] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0046] In addition, the described features, structures or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to give a thorough understanding of the embodiments of the present application. However, those skilled in the art will realize that the technical solutions of the present application can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, well-known methods, devices, implementations or operations are not shown or described in detail to avoid obscuring various aspects of the present application.

[0047] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0048] The flowcharts shown in the drawings are only exemplary illustrations, not necessarily including all the contents and operations / steps, nor necessarily executed in the described order. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined. Therefore, the actual execution order may be changed according to the actual situation.

[0049] Figure 1 The flowchart shows the control method of lubrication flow rate in an embodiment, as Figure 1 shown, a control method of lubrication flow rate is provided, which is applied to a vehicle. The vehicle includes an electric drive system, and the electric drive system includes a planetary gear set and an oil pump. The planetary gear set includes a needle bearing, planetary gears, and a planet carrier. In the planetary gear set, the planetary gears are supported on the pin shafts of the planet carrier by the needle bearing. The control method may include the following steps S101 and S102.

[0050] In step S101, according to the current planet carrier torque, current planet carrier speed, current sun gear torque, and current sun gear speed, determine the current load value of the needle bearing of the planetary gear set.

[0051] It should be noted that the needle bearing supporting the planetary gears in the planetary gear set usually works under the conditions of a closed environment, poor heat dissipation, and variable loads. It is sensitive to the lubrication flow rate and is the most critical part in the lubrication of the entire electric drive system. If the lubrication flow rate can be controlled according to the real-time load borne by the needle bearing, it can not only ensure the reliability of the needle bearing, but also bring benefits to reducing power consumption and improving efficiency of the oil pump system and even the entire powertrain.

[0052] In some embodiments, the electric drive system further includes an engine and a generator. The planet carrier is connected to the engine, and the sun gear is connected to the generator. At this time, the current engine torque can be used as the current planet carrier torque, the current engine speed can be used as the current planet carrier speed, the current generator torque can be used as the current sun gear torque, and the current generator speed can be used as the current sun gear speed. According to the current engine torque, current engine speed, current generator torque, and current generator speed, determine the current load value of the needle bearing.

[0053] In the implementation process, the current generator torque and current generator speed of the generator can be read through the MTCU (Motor and transmission Control Unit), and the current engine torque and current engine speed of the engine can be read through the ECU (Engine Control Unit). Then, according to the read current engine torque, current engine speed, current generator torque, and current generator speed, determine the current load value of the needle bearing of the planetary gear set.

[0054] Figure 2 The structural diagram of the planetary gear set in an embodiment is shown, as Figure 2As shown in the figure, the planetary gear set includes a sun gear shaft 1, a ring gear 2, a carrier 3, planetary gears 3a, needle bearings 3b, carrier pins 3c, a carrier oil passage 3d, and a core oil passage 1a of the sun gear shaft. The needle bearing 3b is disposed between the planetary gear 3a and the carrier pin 3c.

[0055] The lubricating oil injected by the oil pump passes through the core oil passage 1a of the sun gear shaft and is branched to each needle bearing 3b through the carrier oil passage 3d to achieve lubrication of the needle bearing 3b. The lubrication requirements of the needle bearing 3b are mainly related to the force or torque it bears, the rotational speed difference between the inner and outer rings (the inner ring is the outer circle of the carrier pin 3c, and the outer ring is the inner circle of the planetary gear 3a), and the bearing diameter (at the same rotational speed, the larger the bearing diameter, the greater the bearing linear velocity and the longer the friction distance). Since the bearing diameter is a fixed value, only the first two are considered here, and the product of the first two is taken as the load value of the needle bearing 3b. This product can be understood as the work or energy done by the load borne by the needle bearing 3b.

[0056] The load borne by the planetary gear comes from the drive of the carrier and / or the sun gear. Since the sun gear shaft 1 is connected to the generator and the carrier 3 is connected to the engine, the generator torque and generator speed can be correspondingly regarded as the sun gear torque and sun gear speed, and the engine torque and engine speed can be correspondingly regarded as the carrier torque and carrier speed. Given the measured sun gear torque and speed (i.e., the generator torque and speed), and the carrier torque and speed (i.e., the engine torque and engine speed), according to the basic principle of the planetary gear set, the ratio of the sun gear torque to the planetary gear torque T s : T e = -(Z2 / Z1 + 1). The torque transmitted from the sun gear to the planetary gear can be calculated according to the above formula. According to the basic principle of the force on helical gears, based on parameters such as the normal pressure angle α, helix angle β, and pitch diameter d of the planetary gear, the torque can be converted into force. Combining the above torque calculation and force calculation methods, the calculation formula one for the current load value based on the radial force F r of the needle bearing 3b can be obtained.

[0057] Since parameters such as the normal pressure angle α, helix angle β, and pitch diameter d are fixed values, the calculation formula two for the current load value based on the carrier pin torque T n can also be obtained.

[0058] Both of the above two formulas can be used to calculate the current load value borne by the carrier needle bearing.

[0059] In some embodiments, the current load value can be determined according to the current engine torque, current engine speed, current generator torque, current generator speed, the number of teeth of the sun gear, the number of teeth of the ring gear, the normal pressure angle of the planetary gear, the helix angle of the planetary gear, and the pitch diameter of the planetary gear.

[0060] Specifically, the current load value is calculated according to the following formula (1):

[0061]

[0062] where X is the current load value, T e is the current engine torque, T s is the current generator torque, Z1 is the number of teeth of the sun gear, Z2 is the number of teeth of the ring gear, V e is the current engine speed, V s is the current generator speed, α is the normal pressure angle, β is the helix angle, d is the pitch diameter, F r is the radial force of the needle bearing, V n is the speed of the needle bearing (i.e., the difference between the speed of the planetary gear and the speed of the planetary carrier pin).

[0063] In some other embodiments, the speed ratio coefficient can be determined according to the number of teeth of the sun gear and the number of teeth of the ring gear; the current load value can be determined according to the current engine torque, the current engine speed, the current generator torque, the current generator speed, and the speed ratio coefficient.

[0064] Specifically, the current load value is calculated according to the following formula (2):

[0065] X = |(T e - KT s )(V e - V s )|;

[0066] K = -(Z2 / Z1 + 1);

[0067] where X is the current load value, T e is the current engine torque, T s is the current generator torque, K is the speed ratio coefficient, V e is the current engine speed, V s is the current generator speed, T n is the torque of the planetary carrier pin, V n is the speed of the needle bearing (i.e., the difference between the speed of the planetary gear and the speed of the planetary carrier pin).

[0068] In some other embodiments, the electric drive system further includes an electric motor. The planet carrier is connected to the wheel end output shaft, and the sun gear is connected to the electric motor. Determining the current load value of the needle bearing of the planetary gear set according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed includes: using the current wheel end output shaft torque as the current planet carrier torque, using the current wheel end output shaft speed as the current planet carrier speed, using the current electric motor torque as the current sun gear torque, and using the current electric motor speed as the current sun gear speed; determining the current load value of the needle bearing of the planetary gear set according to the current wheel end output shaft torque, the current wheel end output shaft speed, the current electric motor torque, and the current electric motor speed.

[0069] For the specific determination method of the current load value, reference can be made to the above two formulas. Replace the current engine torque in the formulas with the current wheel end output shaft torque, the current engine speed with the current wheel end output shaft speed, the current generator torque with the current electric motor torque, and the current generator speed with the current electric motor speed. This will not be elaborated here.

[0070] It can be understood that this embodiment is applicable to the form where the planetary gear set connects the electric motor and the wheel end output shaft. In this form, the sun gear is connected to the electric motor, and the planet carrier is connected to the wheel end output shaft, which can achieve speed reduction and torque increase from the electric motor to the wheel end.

[0071] In step S102, according to the current load value and the preset relationship curve, the target lubrication flow rate of the oil pump is determined. The preset relationship curve is used to characterize the corresponding relationship between the load value of the needle bearing and the lubrication flow rate, or is used to characterize the corresponding relationship between the load value of the needle bearing and the oil pump speed.

[0072] In some embodiments, a reliability test can be performed on the electric drive system to obtain multiple load values of the needle bearing of the planetary gear set and the corresponding lubrication flow rate or oil pump speed under the condition of passing the reliability test; fitting all the load values and the lubrication flow rate corresponding to the load values, or fitting all the load values and the oil pump speed corresponding to the load values, to obtain the preset relationship curve.

[0073] Specifically, through reliability tests such as durability and gear bearing sintering, it can be confirmed the oil pump speed required for the electric drive system of the vehicle to pass the test under working conditions with different load values, or the flow rate from the needle bearing to the lubrication position required. Thus, the oil pump speed or the lubrication flow rate of the needle bearing corresponding to each load value can be obtained, and further the relationship curve between the load value and the oil pump speed, or the relationship curve between the load value and the lubrication flow rate can be determined.

[0074] Figure 3 Shows a schematic diagram of the preset relationship curve in an embodiment, as Figure 3As shown, through fitting, the relationship preset relationship curve Y = A * ln(X) - B can be obtained, where Y is the oil pump speed, X is the load value (i.e., the PV value), and A and B are constants fitted according to actual data. For different scenarios or objects, these constants are different.

[0075] In some embodiments, when the preset relationship curve is used to represent the correspondence between the load value of the needle roller bearing and the lubrication flow rate, the lubrication flow rate corresponding to the current load value is determined from the preset relationship curve, and the determined lubrication flow rate is used as the target lubrication flow rate of the needle roller bearing.

[0076] In other embodiments, when the preset relationship curve is used to represent the correspondence between the load value of the needle roller bearing and the oil pump speed, the oil pump speed corresponding to the current load value is determined from the preset relationship curve, and based on the determined oil pump speed, the target lubrication flow rate of the needle roller bearing is obtained.

[0077] Return for reference Figure 3 , according to the preset relationship curve Y = A * ln(X) - B and the current load value X1, the oil pump speed Y1 corresponding to the current load value X1 can be calculated. It can be understood that if the oil pump speed meets the lubrication flow rate of the needle roller bearing, it basically meets the lubrication flow rate of the planetary gear set as well. Therefore, based on the relationship between the lubrication flow rate and the oil pump speed of the needle roller bearing, the lubrication flow rate corresponding to the oil pump speed Y1 can be calculated, and the calculated lubrication flow rate is used as the target lubrication flow rate.

[0078] In the embodiments of the present application, the current load value of the needle roller bearing is determined according to the current engine torque, current engine speed, current generator torque, and current generator speed; according to the current load value and the preset relationship curve, the target lubrication flow rate of the needle roller bearing is determined, and the preset relationship curve is used to represent the correspondence between the load value of the needle roller bearing and the lubrication flow rate, or to represent the correspondence between the load value of the needle roller bearing and the oil pump speed. Through the technical solution provided by the present application, precise quantitative control of the lubrication flow rate is performed according to the current load value borne by the needle roller bearing of the planetary gear set, which not only ensures the reliability of the needle roller bearing but also reduces the power consumption of the vehicle.

[0079] Figure 4 Shows a schematic flowchart of the control method of the lubrication flow rate in another embodiment. As Figure 4 shown, the control method of the lubrication flow rate may further include the following steps:

[0080] Step 401, determine the current load value of the needle roller bearing of the planetary gear set according to the current planet carrier torque, current planet carrier speed, current sun gear torque, and current sun gear speed;

[0081] Step 402: Determine the target lubrication flow rate of the needle roller bearing according to the current load value and the preset relationship curve. The preset relationship curve is used to represent the corresponding relationship between the load value of the needle roller bearing and the lubrication flow rate, or is used to represent the corresponding relationship between the load value of the needle roller bearing and the rotational speed of the oil pump.

[0082] Step 403: Control the target rotational speed of the oil pump according to the target lubrication flow rate.

[0083] Figure 5 shows Figure 4 the schematic diagram of the data flow in Figure 5 As shown, the ECU reads the current engine torque and the current engine speed, and interacts this data with the MTCU. The MTCU reads the current generator torque and the current generator speed. The MTCU calculates the current load value of the needle roller bearing based on the relevant data of the engine and the generator according to Formula 1 or Formula 2, and determines the flow rate (i.e., the target lubrication flow rate) that meets the lubrication requirement of the needle roller bearing of the planetary gear set according to the preset relationship curve. Then, it calculates the first rotational speed required for the oil pump to meet the target lubrication flow rate, obtains the second rotational speed required for the oil pump to meet the motor cooling requirement, and the third rotational speed required for the oil pump to meet other requirements, and takes the larger value among the first rotational speed, the second rotational speed, and the third rotational speed as the target rotational speed of the oil pump. Finally, it controls the operation of the motor of the electric oil pump according to the target rotational speed.

[0084] In the embodiment of the present application, by determining the target lubrication flow rate of the needle roller bearing according to the current load value of the needle roller bearing, and then controlling the target rotational speed of the oil pump based on the target lubrication flow rate, the power consumption of the electric drive system and the whole vehicle is reduced.

[0085] The following introduces the device embodiment of the present application, which can be used to execute the lubrication flow rate control method in the above embodiments of the present application. For the details not disclosed in the device embodiment of the present application, please refer to the embodiment of the lubrication flow rate control method in the above of the present application.

[0086] See Figure 6 which shows the block diagram of the lubrication flow rate control device in the embodiment of the present application.

[0087] As Figure 6As shown in the figure, the lubricating flow control device of the embodiment of the present application is applied to a vehicle. The vehicle includes an electric drive system, and the electric drive system includes a planetary gear set and an oil pump. In the planetary gear set, the planetary gears are supported on the pin shafts of the planet carrier through needle bearings. The lubricating flow control device includes a needle bearing load determination unit 601 and a lubricating flow determination unit 602. Among them, the needle bearing load determination unit 601 is used to determine the current load value of the needle bearings of the planetary gear set according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed. The lubricating flow determination unit 602 is used to determine the target lubricating flow of the needle bearings according to the current load value and a preset relationship curve. The preset relationship curve is used to represent the corresponding relationship between the load value of the needle bearings and the lubricating flow, or is used to represent the corresponding relationship between the load value of the needle bearings and the oil pump speed.

[0088] In some embodiments of the present application, based on the foregoing solution, the electric drive system further includes an engine and a generator. The planet carrier is connected to the engine, and the sun gear is connected to the generator. The needle bearing load determination unit 601 is further used to use the current engine torque as the current planet carrier torque, use the current engine speed as the current planet carrier speed, use the current generator torque as the current sun gear torque, and use the current generator speed as the current sun gear speed. According to the current engine torque, the current engine speed, the current generator torque, the current generator speed, the number of teeth of the sun gear, the number of teeth of the ring gear, the normal pressure angle of the planetary gear, the helix angle of the planetary gear, and the pitch diameter of the planetary gear, determine the current load value.

[0089] In some embodiments of the present application, based on the foregoing solution, the current load value is calculated according to the following formula:

[0090]

[0091] Among them, X is the current load value, T e is the current engine torque, T s is the current generator torque, Z1 is the number of teeth of the sun gear, Z2 is the number of teeth of the ring gear, V e is the current engine speed, V s is the current generator speed, α is the normal pressure angle, β is the helix angle, and d is the pitch diameter.

[0092] In some embodiments of the present application, based on the foregoing solution, the electric drive system further includes an engine and a generator. The planet carrier is connected to the engine, the sun gear is connected to the generator, and the needle roller bearing load determination unit 601 is further configured to use the current engine torque as the current planet carrier torque, the current engine speed as the current planet carrier speed, the current generator torque as the current sun gear torque, and the current generator speed as the current sun gear speed; determine the speed ratio coefficient according to the number of teeth of the sun gear and the number of teeth of the ring gear; determine the current load value according to the current engine torque, the current engine speed, the current generator torque, the current generator speed, and the speed ratio coefficient.

[0093] In some embodiments of the present application, based on the foregoing solution, the current load value is calculated according to the following formula:

[0094] X = |(T e - KT s )(V e - V s )|;

[0095] K = -(Z2 / Z1 + 1);

[0096] Wherein, X is the current load value, T e is the current engine torque, T s is the current generator torque, K is the speed ratio coefficient, V e is the current engine speed, V s is the current generator speed, Z1 is the number of teeth of the sun gear, and Z2 is the number of teeth of the ring gear.

[0097] In some embodiments of the present application, based on the foregoing solution, the electric drive system further includes a motor. The planet carrier is connected to the wheel end output shaft, the sun gear is connected to the motor, and the needle roller bearing load determination unit 601 is further configured to use the current wheel end output shaft torque as the current planet carrier torque, the current wheel end output shaft speed as the current planet carrier speed, the current motor torque as the current sun gear torque, and the current motor speed as the current sun gear speed; determine the current load value of the needle roller bearing of the planetary gear set according to the current wheel end output shaft torque, the current wheel end output shaft speed, the current motor torque, and the current motor speed.

[0098] In some embodiments of the present application, based on the foregoing solution, the lubricating flow rate determination unit 602 is further configured to, when the preset relationship curve is used to represent the corresponding relationship between the load value of the needle roller bearing and the lubricating flow rate, determine the lubricating flow rate corresponding to the current load value from the preset relationship curve, and use the determined lubricating flow rate as the target lubricating flow rate of the needle roller bearing;

[0099] When the preset relationship curve is used to characterize the correspondence between the load value of the needle roller bearing and the oil pump speed, the oil pump speed corresponding to the current load value is determined from the preset relationship curve, and the target lubrication flow rate of the needle roller bearing is obtained according to the determined oil pump speed.

[0100] In some embodiments of the present application, based on the foregoing solution, the control device for the lubrication flow rate further includes: a preset relationship curve determination unit, configured to perform a reliability test on the electric drive system to obtain multiple load values of the needle roller bearings of the planetary gear set and the lubrication flow rate or the oil pump speed corresponding to each load value when passing the reliability test; fit all the load values and the lubrication flow rate corresponding to the load values, or fit all the load values and the oil pump speed corresponding to the load values, to obtain the preset relationship curve.

[0101] In some embodiments of the present application, based on the foregoing solution, the control device for the lubrication flow rate further includes: an oil pump control unit, configured to control the target speed of the oil pump according to the target lubrication flow rate.

[0102] Based on the same inventive concept, embodiments of the present application further provide a control device for the lubrication flow rate. Refer to Figure 7 , which shows a schematic structural diagram of the control device for the lubrication flow rate in the embodiments of the present application. The control device for the lubrication flow rate includes one or more memories 704, one or more processors 702, and at least one computer program (computer program instructions) stored on the memory 704 and executable on the processor 702. When the processor 702 executes the computer program, the method as described above is implemented.

[0103] Among them, in Figure 7 , the bus architecture (represented by the bus 700), the bus 700 may include any number of interconnected buses and bridges, and the bus 700 links various circuits including one or more processors represented by the processor 702 and the memory represented by the memory 704 together. The bus 700 can also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art, and thus will not be further described herein. The bus interface 705 provides an interface between the bus 700 and the receiver 701 and the transmitter 703. The receiver 701 and the transmitter 703 can be the same element, that is, a transceiver, providing a unit for communicating with various other devices on the transmission medium. The processor 702 is responsible for managing the bus 700 and general processing, and the memory 704 can be used to store data used by the processor 702 when performing operations.

[0104] Based on the same inventive concept, an embodiment of the present application provides a computer-readable storage medium, in which computer program instructions are stored. When the computer program instructions are executed by a processor, the processor is caused to implement the steps of the method as described above.

[0105] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on a computer-readable medium or transmitted via a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope and spirit of the present application and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these. In addition, each functional unit can be integrated in one processing unit, or can exist physically separately for each unit, or two or more units can be integrated in one unit.

[0106] In several embodiments provided by the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are merely illustrative. For example, the division of the units can be a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the couplings or direct couplings or communication connections shown or discussed with each other can be through some interfaces. The indirect couplings or communication connections of units or modules can be in an electrical or other form.

[0107] The units described as separate components may or may not be physically separated. The components serving as control devices may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0108] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs that can store computer program instructions.

[0109] The above are only the embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A control method for lubrication flow rate, applied to a vehicle, characterized in that, The vehicle includes an electric drive system, which includes a planetary gear set, an oil pump, an engine, and a generator. In the planetary gear set, the planetary gears are supported on the pin shafts of the planet carrier through needle bearings. The planet carrier is connected to the engine, and the sun gear is connected to the generator. The control method includes: Determine the current load value of the needle bearing of the planetary gear set according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed; Determine the target lubrication flow rate of the needle bearing according to the current load value and a preset relationship curve. The preset relationship curve is used to characterize the corresponding relationship between the load value and the lubrication flow rate of the needle bearing, or is used to characterize the corresponding relationship between the load value and the oil pump speed of the needle bearing; The step of determining the current load value of the needle bearing of the planetary gear set according to the current planet carrier torque, the current planet carrier speed, the current sun gear torque, and the current sun gear speed includes: Take the current engine torque as the current planet carrier torque, take the current engine speed as the current planet carrier speed, take the current generator torque as the current sun gear torque, and take the current generator speed as the current sun gear speed; Determine the current load value according to the current engine torque, the current engine speed, the current generator torque, the current generator speed, the number of teeth of the sun gear, the number of teeth of the ring gear, the normal pressure angle of the planetary gear, the helix angle of the planetary gear, and the pitch diameter of the planetary gear, or determine a speed ratio coefficient according to the number of teeth of the sun gear and the number of teeth of the ring gear, and determine the current load value according to the current engine torque, the current engine speed, the current generator torque, the current generator speed, and the speed ratio coefficient.

2. The control method of lubrication flow rate according to claim 1, wherein The current load value is calculated according to the following formula: wherein, X is the current load value, T e is the current engine torque, T s is the current generator torque, Z1 is the number of teeth of the sun gear, Z2 is the number of teeth of the ring gear, V e is the current engine speed, V s is the current generator speed, α is the normal pressure angle, β is the helix angle, and d is the pitch circle diameter.

3. The control method of lubrication flow rate according to claim 1, characterized in that, The current load value is calculated according to the following formula: X = |(T e -KT s )(V e -V s )|; K = -(Z2 / Z1 + 1); Wherein, X is the current load value, T e is the current engine torque, T s is the current generator torque, K is the speed ratio coefficient, V e is the current engine speed, V s is the current generator speed, Z1 is the number of teeth of the sun gear, and Z2 is the number of teeth of the ring gear.

4. The control method of lubricating flow rate according to any one of claims 1 to 3, characterized in that, The step of determining the target lubrication flow rate of the needle bearing according to the current load value and a preset relationship curve includes: When the preset relationship curve is used to characterize the corresponding relationship between the load value and the lubrication flow rate of the needle bearing, determine the lubrication flow rate corresponding to the current load value from the preset relationship curve, and take the determined lubrication flow rate as the target lubrication flow rate of the needle bearing; When the preset relationship curve is used to characterize the corresponding relationship between the load value and the oil pump speed of the needle bearing, determine the oil pump speed corresponding to the current load value from the preset relationship curve, and obtain the target lubrication flow rate of the needle bearing according to the determined oil pump speed.

5. The control method of lubrication flow rate according to any one of claims 1 to 3, characterized in that, The control method further includes: Conduct a reliability test on the electric drive system to obtain multiple load values of the needle bearing of the planetary gear set and the corresponding lubrication flow rate or oil pump speed of each load value under the condition of passing the reliability test; Fit all the load values and the lubrication flow rates corresponding to the load values, or fit all the load values and the pump speeds corresponding to the load values to obtain the preset relationship curve.

6. The control method of lubrication flow rate according to any one of claims 1 to 3, characterized in that, The control method further includes: Controlling the target speed of the oil pump according to the target lubrication flow rate.

7. A control device for lubrication flow rate, comprising a processor and a memory, characterized in that, The memory stores computer program instructions executable by the processor, and when the processor executes the computer program instructions, the steps of the method according to any one of claims 1 to 6 are implemented.

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