Electric drive axle flow adaptive system

Abstract

The utility model relates to the technical field of commercial vehicle electric drive axle, disclose electric drive axle flow adaptive system, including lubrication spare part, main oil circuit, a plurality of branch and electronic control unit, the main oil circuit is connected with oil sump, electronic oil pump and oil cooler in proper order through oil channel, the branch is led out from oil cooler export, and each branch is in parallel setting, and each branch is connected electromagnetic valve, pressure compensation valve, throttle hole and corresponding lubrication spare part in proper order through oil channel, electronic control unit is connected with oil temperature sensor, oil pressure sensor, each electromagnetic valve and electronic oil pump. Electric drive axle flow adaptive system of the utility model carries out hierarchical control to different working conditions, and adjusts electronic oil pump rotating speed in real time, and electronic oil pump power adaptive compensation, each circuit can be independently controlled, adopts the structure of valve after compensation, guarantees the accurate distribution of flow according to proportion, is not affected by load, and reduces throttling and overflow loss, reduces system power consumption.

Description

Technical Field

[0001] This utility model relates to the field of electric drive axle technology for commercial vehicles, and specifically to an electric drive axle flow adaptive system. Background Technology

[0002] There are two common methods for cooling motors: oil cooling and water cooling. Water-cooled motors are indirectly cooled through cooling water channels on the water jacket of the stator outer perimeter. This method has a long heat transfer path and lower heat dissipation efficiency, but it is low in cost. Oil-cooled motors are cooled by direct spraying of lubricating oil onto the stator windings for contact heat exchange. This method has high heat dissipation capacity and higher efficiency than water cooling.

[0003] Lubrication methods for bearings and gears are generally divided into active lubrication and passive lubrication. Active lubrication uses an oil pump to force oil into the oil passages, which then pass through oil coolers, spray channels, and throttling orifices before being introduced into each friction pair to lubricate and cool the components. This method is commonly found in high-power, high-performance, and structurally complex multi-stage reducers. Passive lubrication, on the other hand, does not require additional oil circuit design. The rotation of gears splashes oil, which then passes through rationally designed oil passages or guide plates to achieve lubrication and cooling of bearings and gears. This method is commonly found in low-to-medium power, low-cost, and structurally simple reducers.

[0004] Currently, high-power integrated electric drive bridge products on the market mainly employ two types of lubrication and cooling systems: 1. Independent oil cooling for the motor and separate lubrication for the reducer, requiring two sets of oil pump circulation systems with separate chamber designs, resulting in a complex structure. While the motor flow can be precisely controlled, the cost is high. 2. A shared chamber design for the motor and reducer, using only one oil pump control system, which is low-cost but involves many nodes, significant differences in flow resistance between oil circuits, and is greatly affected by oil temperature, leading to inaccurate flow distribution. Utility Model Content

[0005] To address the technical problems mentioned in the background section, the present invention provides an adaptive flow system for an electric drive bridge, comprising lubrication components, a main oil circuit, multiple branch circuits, and an electronic control unit. The main oil circuit is sequentially connected to an oil pan, an electronic oil pump, and an oil cooler via oil passages. A safety valve, an oil temperature sensor, and an oil pressure sensor are also sequentially connected to the main oil circuit via oil passages. The branch circuits extend from the oil cooler outlet and are arranged in parallel. Each branch circuit is sequentially connected to a solenoid valve, a pressure compensation valve, a throttle orifice, and corresponding lubrication components via oil passages. The electronic control unit is connected to the oil temperature sensor, the oil pressure sensor, the solenoid valves, and the electronic oil pump.

[0006] Optionally, the branch includes a second branch, a third branch, a fourth branch, and a fifth branch, wherein the second branch is led out from the oil cooler and connected in sequence to the first solenoid valve and the first pressure compensation valve. The outlet of the first compensation valve is connected in parallel to the first throttling orifice and the second throttling orifice, which are respectively connected to their lubrication components. The third branch is led out from the oil cooler and connected in sequence to the second solenoid valve and the second pressure compensation valve. The outlet of the second pressure compensation valve is connected in parallel to the third throttle orifice and the fourth throttle orifice, which are respectively connected to their lubrication components. The fourth branch is led out from the oil cooler and connected in sequence to the third solenoid valve and the third pressure compensation valve. The outlet of the third pressure compensation valve is connected in parallel to the fifth throttling orifice and the sixth throttling orifice, which are respectively connected to their lubrication components. The fifth branch is led out from the oil cooler, which is equipped with a ninth throttling orifice. The seventh and eighth throttling orifices are connected in parallel at the rear end of the throttling orifice, and the seventh and eighth throttling orifices are respectively connected to its lubrication components.

[0007] Optionally, a shuttle valve network is provided between the second branch, the third branch, and the fourth branch, specifically including a first shuttle valve and a second shuttle valve. The first shuttle valve is connected to the rear end of the first compensation valve, the first compensation valve, the second compensation valve, the third compensation valve, and the second shuttle valve of the second branch. The second shuttle valve is connected to the rear end of the second compensation valve of the third branch and the rear end of the third compensation valve of the fourth branch.

[0008] Optionally, the third branch and the fifth branch are connected, and a first check valve is provided at the connection point; the fourth branch and the fifth branch are connected, and a second check valve is provided at the connection point.

[0009] Optionally, the oil cooler is connected to bypass valves at both ends.

[0010] The control method for an electric drive bridge flow adaptive system includes the following steps: S1. Detect and read various signal values ​​under the current operating conditions, including motor input speed, motor input torque, motor temperature, oil temperature, and gear position; S2. The motor efficiency matrix and the efficiency matrix of each gear and bearing under each operating condition obtained from the test or simulation data are put into the calculation module of the electronic control unit as a table, and the efficiency value under the specific operating condition is calculated by interpolation. Based on the power, the motor efficiency loss Φ_motor, the gear meshing efficiency loss Φ_gear and the bearing efficiency loss Φ_bearing are obtained. S31. The motor cooling flow requirement is derived based on thermal balance and efficiency loss: Q_cool =Φ_x / (ρ×c×Δt), In the formula, ρ is the density of lubricating oil, c is the specific heat capacity of lubricating oil, Δt is the target temperature rise, and Φ_x is the efficiency loss of the working part. S32. The bearing lubrication flow rate is derived based on empirical coefficients from experimental values: Q 轴 _lube=k1×d×B×n, In the formula, d is the bearing inner diameter, B is the bearing width, n is the rotational speed, and k is an empirical coefficient; Gear meshing lubrication flow rate: Q 齿 _lube=k2×b×m×v×Z, where b is the tooth width, m is the module, v is the pitch circle linear velocity, Z is the correction coefficient, and k is the base coefficient; S33. Compare Q_cool and Q_lube of the bearing and gear respectively, and take the larger one as the target flow rate Qi=max[Q_cool, Q_lube].

[0011] S41. Calculate the total flow requirement of the electronic oil pump Q1=ΣQi+Q_motor, and determine the initial operating speed n0=Q1 / (η_v0×V_p), where V_p is the oil pump displacement, η_v0 is the average volumetric efficiency, and Q_motor is the motor cooling flow rate. S42. Calculate the flow requirements Q2, Q3, and Q4 for the second, third, and fourth branches, and determine the first solenoid valve, the first solenoid valve, and the opening degree of the first solenoid valve. S5. After the opening degree of the first solenoid valve and the speed of the electronic oil pump are determined, the pressure of the oil pressure sensor is also determined accordingly. Based on the oil temperature at this time, the actual efficiency η_v1 of the electronic oil pump can be obtained by referring to the table. At this time, the working speed of the oil pump is n1=Q1 / (η_v1×V_p). The compensation speed Δn=n1-n0 is determined in this way to complete the power compensation and achieve precise control. S6. Repeat this process, adjusting the speed of the electronic oil pump and the opening of the solenoid valve in real time.

[0012] In summary, the electric drive bridge flow adaptive system of this utility model provides graded control for different working conditions and adjusts the speed of the electronic oil pump in real time, with adaptive compensation for the power (flow) of the electronic oil pump. Each circuit can be controlled independently, and the structure of post-valve compensation ensures that the flow is accurately distributed proportionally, unaffected by the load (oil viscosity-temperature characteristics), and reduces throttling and overflow losses, thereby reducing system power consumption. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the electric drive bridge flow adaptive system of this utility model; Figure 2 This is a flowchart of the control method for the electric drive bridge flow adaptive system of this utility model; In the diagram: 10. Oil pan; 11. Electronic oil pump; 12. Bypass valve; 13. Oil cooler; 14. Safety valve; 15. Oil temperature sensor; 16. Oil pressure sensor; 21. First solenoid valve; 22. First pressure compensation valve; 23. First throttle orifice; 24. Second throttle orifice; 25. First shuttle valve; 31. Second solenoid valve; 32. Second pressure compensation valve; 33. Third throttle orifice; 34. Fourth throttle orifice; 35. Second shuttle valve; 41. Third solenoid valve; 42. Third pressure compensation valve; 43. Fifth throttle orifice; 44. Sixth throttle orifice; 51. Ninth throttle orifice; 52. First check valve; 53. Second check valve; 54. Seventh throttle orifice; 55. Eighth throttle orifice. Detailed Implementation

[0014] The following combination Figure 1-2 The present invention will be described in further detail below.

[0015] This utility model discloses an electric drive bridge flow adaptive system that matches the opening degree of the solenoid valve in real time under any overall machine operating condition. Pressure compensation valves and shuttle valves are installed at the inlet and outlet to maintain a constant pressure difference, ensuring it is unaffected by temperature or load changes. This guarantees precise allocation of flow to components at each flow demand point, reducing throttling losses. The electronic oil pump calculates the operating speed in real time based on the operating conditions and compensates for the speed in real time through oil temperature and pressure, achieving high efficiency and energy saving. Figure 1 The system includes lubrication components, a main oil circuit, multiple branch circuits, and an electronic control unit. The main oil circuit is connected in sequence to an oil pan 10, an electronic oil pump 11, and an oil cooler 13 via oil passages. A bypass valve 12 is connected to both ends of the oil cooler 13. A safety valve 14, an oil temperature sensor 15, and an oil pressure sensor 16 are also connected in sequence to the main oil circuit via oil passages. The branch circuits are led out from the outlet of the oil cooler 13 and are arranged in parallel. Each branch circuit is connected in sequence to a solenoid valve, a pressure compensation valve, a throttle orifice, and the corresponding lubrication components via oil passages. The electronic control unit is connected to the oil temperature sensor 15, the oil pressure sensor 16, each solenoid valve, and the electronic oil pump 11. The electronic control unit is used for collecting various operating condition information variables of the electric drive axle assembly, inputting oil temperature signal 1 and oil pressure signal 2, outputting control signals for solenoid valves b, c, and d, and outputting control signal a for the oil pump.

[0016] In a further embodiment, the branch includes a second branch, a third branch, a fourth branch, and a fifth branch. The second branch is led out from the oil cooler 13 and connected in sequence to the first solenoid valve 21 and the first pressure compensation valve 22. The outlet of the first compensation valve 22 is connected in parallel to the first throttling orifice 23 and the second throttling orifice 24. The first throttling orifice 23 and the second throttling orifice 24 are respectively connected to their lubricated components (motor stator and motor rotor). The third branch is led out from the oil cooler 13 and connected in sequence to the second solenoid valve 31 and the second pressure compensation valve 32. The outlet of the second pressure compensation valve 32 is connected in parallel to the third throttle orifice 33 and the fourth throttle orifice 34. The third throttle orifice 33 and the fourth throttle orifice 34 are respectively connected to their lubrication components (first gear set and first bearing). The fourth branch is led out from the oil cooler 13 and connected in sequence to the third solenoid valve 41 and the third pressure compensation valve 42. The outlet of the third pressure compensation valve 42 is connected in parallel to the fifth throttle orifice 43 and the sixth throttle orifice 44. The fifth throttle orifice 43 and the sixth throttle orifice 44 are respectively connected to their lubricating components (second gear set and second bearing). The fifth branch is led out from the oil cooler 13, which is provided with a throttling orifice 51. The rear end of the throttling orifice 51 is connected to the seventh throttling orifice 54 and the eighth throttling orifice 55. The seventh throttling orifice 54 and the eighth throttling orifice 55 are respectively connected to their lubricating components (shared gear set and shared bearing).

[0017] In a further embodiment, a shuttle valve network is provided between the second branch, the third branch, and the fourth branch, specifically including a first shuttle valve 25 and a second shuttle valve 35. The first shuttle valve 25 is connected to the rear end of the first compensating valve 22, the first compensating valve 22, the second compensating valve 32, the third compensating valve 42, and the second shuttle valve 35 of the second branch. The second shuttle valve 35 is connected to the rear end of the second compensating valve 32 of the third branch and the rear end of the third compensating valve 42 of the fourth branch. The third branch and the fifth branch are connected, and a first check valve 52 is provided at the connection point. The fourth branch and the fifth branch are connected, and a second check valve 53 is provided at the connection point.

[0018] Specifically, the electric drive bridge flow adaptive system of this utility model draws lubricating oil from the oil pan 10 through the electronic oil pump 11 and then pumps it out. The oil passes through the oil cooler 13 or the bypass valve 12 and enters each branch. Each solenoid valve is a 2-position, 2-way proportional flow valve. The flow is distributed to the motor stator and motor rotor through the main oil circuit via the first solenoid valve 21, the first pressure compensation valve 22, the first throttle orifice 23, and the second throttle orifice 24. The flow is also distributed to the first gear set and the first bearing position through the second solenoid valve 31, the second pressure compensation valve 32, the third throttle orifice 33, and the fourth throttle orifice 34. Finally, the flow is distributed to the second gear through the third solenoid valve 41, the third pressure compensation valve 42, the fifth throttle orifice 43, and the sixth throttle orifice 44. The positions of the gear set and the second gear bearing are specified. The flow rate is distributed from the main oil circuit through the ninth throttle orifice 51, the seventh throttle orifice 54 and the eighth throttle orifice 55 to the common operating gear set (hereinafter referred to as the common gear set) and the common operating bearing (hereinafter referred to as the common bearing) when working in neutral or geared mode. The first check valve 52 is used to receive the flow rate of the third branch and prevent reverse flow, and the second check valve 53 is used to receive the flow rate of the fourth branch and prevent reverse flow. The network composed of the first shuttle valve 25 and the second shuttle valve 35 is used to select the highest pressure of the second, third and fourth branches. This pressure is applied to the first compensation valve 21, the second compensation valve 31 and the third compensation valve 41 to resist the flow rate problem caused by load changes and ensure that each branch is accurately distributed proportionally.

[0019] During operation, the electric drive axle / reducer calculates the flow requirements of each component and the total flow requirements under the current gear, temperature, motor torque, and speed through processing and logical judgment of real-time input information. This enables adaptive flow allocation with temperature and power compensation. The main functions are: ① Based on the current total flow demand, current temperature and pressure, determine the power of the electronic oil pump 11, adjust its output speed in real time, and complete the power compensation of the electronic oil pump. ② Determine the opening degree of the solenoid valves in the second, third, and fourth branches according to the flow requirements of the components to achieve hierarchical control and on-demand allocation; ③ By using the shuttle valve network and pressure compensation valve installed on the second, third and fourth branches, the pressure difference before and after each solenoid valve is the same, so that it is not affected by the load (load change caused by oil temperature and viscosity change), and temperature compensation is achieved.

[0020] The electric drive bridge flow adaptive system of this utility model can realize adaptive stepless control of the electronic oil pump and solenoid valve, and match the flow demand in real time. Figure 2 The specific control methods include the following steps: S1. Detect and read various signal values ​​under the current operating conditions, including motor input speed, motor input torque, motor temperature, oil temperature, and gear position; S2. The motor efficiency matrix and the efficiency matrix of each gear and bearing under each operating condition obtained from the test or simulation data are put into the calculation module of the electronic control unit as a table, and the efficiency value under the specific operating condition is calculated by interpolation. Based on the power, the motor efficiency loss Φ_motor, the gear meshing efficiency loss Φ_gear and the bearing efficiency loss Φ_bearing are obtained. S31. The motor cooling flow requirement is derived based on thermal balance and efficiency loss: Q_cool =Φ_x / (ρ×c×Δt), In the formula, ρ is the density of lubricating oil, c is the specific heat capacity of lubricating oil, Δt is the target temperature rise, and Φ_x is the efficiency loss of the working part. S32. The bearing lubrication flow rate is derived based on empirical coefficients from experimental values: Q 轴 _lube=k1×d×B×n, In the formula, d is the bearing inner diameter, B is the bearing width, n is the rotational speed, and k is an empirical coefficient; Gear meshing lubrication flow rate: Q 齿 _lube=k2×b×m×v×Z, where b is the tooth width, m is the module, v is the pitch circle linear velocity, Z is the correction coefficient, and k is the base coefficient; S33. Compare Q_cool and Q_lube of the bearing and gear respectively, and take the larger one as the target flow rate Qi=max[Q_cool, Q_lube].

[0021] S41. Calculate the total flow requirement of the electronic oil pump 11, Q1 = ΣQi + Q_motor, and determine the initial operating speed n0 = Q1 / (η_v0 × V_p), where V_p is the pump displacement, η_v0 is the average volumetric efficiency, and Q_motor is the motor cooling flow rate (Q_cool). ΣQi = Q 轴 +Q 齿 ; Specifically, the total flow requirement of the electronic oil pump 11 includes two parts: motor + gear bearing; the motor only needs cooling; while the gear and bearing need both cooling and lubrication. The cooling flow of the two is the motor cooling flow. The maximum value of the cooling flow requirement and the lubrication flow requirement can be taken. The total flow of the electronic oil pump 11 is obtained by adding the motor flow requirement, the bearing flow requirement and the gear flow requirement. S42. Calculate the flow requirements Q2, Q3, and Q4 for the second, third, and fourth branches, and determine the opening degree (control current) of the first solenoid valve 22, the first solenoid valve 32, and the first solenoid valve 42. S5. After the opening degree of the first solenoid valve 22, the second solenoid valve 32 and the third solenoid valve 42 and the speed of the electronic oil pump 11 are determined, the pressure of the oil pressure sensor 16 is also determined accordingly. Based on the oil temperature at this time, the actual efficiency η_v1 of the electronic oil pump 11 can be obtained by referring to the table (based on the test value). At this time, the working speed of the oil pump n1=Q1 / (η_v1×V_p) is used to determine the compensation speed Δn=n1-n0, so as to complete the power (speed) compensation and achieve precise control. S6. Repeat this process, adjusting the speed of the electronic oil pump 11 and the opening of the solenoid valve in real time.

[0022] The typical control method of this utility model is as follows: I. Self-lubrication in idle / standby mode The first solenoid valve 22, the second solenoid valve 32, and the third solenoid valve 42 are closed, the oil pump operates at low power (speed), and only the fifth branch is open to maintain the basic lubrication flow of the common gear set and common bearing structural components, thereby minimizing power consumption.

[0023] II. Driving in first gear with a load The third solenoid valve 42 is closed, and the fourth branch is not conductive. The total flow demand is calculated in real time based on the current operating conditions, thereby determining the flow demand of the second, third, and fifth branches. This controls the speed of the electronic oil pump 11 and the opening of the first solenoid valve 22 and the second solenoid valve 32, respectively, to achieve precise on-demand control. The flow of the fifth branch consists of two parts: most of it is distributed from the third branch through the first one-way valve 52, and a small portion is the basic lubricating oil volume distributed by the throttle orifice 51. This working mode can be extended to the first gear no-load driving state. At this time, the second branch is completely closed, and only the third and fifth branches are working. The flow demand is determined based on the no-load coasting speed, thereby determining the speed of the electronic oil pump 11 and the opening of the second solenoid valve 32.

[0024] Third, second gear with load. The second solenoid valve 32 is closed, and the third branch is not conductive. The total flow demand is calculated in real-time based on the current operating conditions, thereby determining the flow demands of the second, fourth, and fifth branches. This controls the speed of the electronic oil pump 11 and the opening degrees of the first and third solenoid valves 22 and 42, respectively, achieving precise on-demand control. Similarly, the flow in the fifth branch consists of two parts: most of it is distributed from the fourth branch via the second check valve 53, and a smaller portion is the basic lubricating oil volume distributed by the throttle orifice 51. This operating mode can also be extended to the second-gear no-load driving state. In this state, the second branch is completely closed, and only the fourth and fifth branches operate. The flow demand is determined based on the no-load coasting speed, thereby determining the speed of the electronic oil pump 11 and the opening degrees of the first and third solenoid valves 22 and 42.

[0025] IV. Low-temperature cold start During low-temperature startup, if the oil viscosity is high at -40℃, the oil pump will be under heavy load. The electronic oil pump 11 will often only be able to rotate at low speed, and the speed fluctuation will be large, making it difficult to provide the necessary lubrication flow. In this invention, if an excessively low oil temperature is detected, the second solenoid valve 32 and the third solenoid valve 42 will be actively closed, and the third and fourth branches will not be connected. This reduces the number of outlet branches, allowing the oil to flow more rapidly to the second and fifth branches. The oil then returns to the oil pan 10 through the motor circuit in the second branch. At this time, the motor controller enters the heat engine mode, applying a large current to the motor at low speed for continuous heating. The oil is heated in this way, rapidly heating the oil and improving the cold start capability.

[0026] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. An electric drive bridge flow adaptive system, characterized in that, It includes lubricating components, a main oil circuit, multiple branch circuits and an electronic control unit. The main oil circuit is connected in sequence to an oil pan (10), an electronic oil pump (11) and an oil cooler (13) via oil passages. The main oil circuit is also connected in sequence to a safety valve (14), an oil temperature sensor (15) and an oil pressure sensor (16) via oil passages. The branch circuits are led out from the outlet of the oil cooler (13) and are arranged in parallel. Each branch circuit is connected in sequence to a solenoid valve, a pressure compensation valve, a throttle orifice and the corresponding lubricating components via oil passages. The electronic control unit is connected to the oil temperature sensor (15), the oil pressure sensor (16), each solenoid valve and the electronic oil pump (11).

2. The electric drive bridge flow adaptive system according to claim 1, characterized in that, The branch includes a second branch, a third branch, a fourth branch and a fifth branch. The second branch is led out from the oil cooler (13) and connected in sequence to the first solenoid valve (21) and the first pressure compensation valve (22). The outlet of the first pressure compensation valve (22) is connected in parallel to the first throttling orifice (23) and the second throttling orifice (24). The first throttling orifice (23) and the second throttling orifice (24) are respectively connected to their lubrication components. The third branch is led out from the oil cooler (13) and connected in sequence to the second solenoid valve (31) and the second pressure compensation valve (32). The outlet of the second pressure compensation valve (32) is connected in parallel to the third throttle orifice (33) and the fourth throttle orifice (34). The third throttle orifice (33) and the fourth throttle orifice (34) are respectively connected to their lubrication components. The fourth branch is led out from the oil cooler (13) and connected in sequence to the third solenoid valve (41) and the third pressure compensation valve (42). The outlet of the third pressure compensation valve (42) is connected in parallel to the fifth throttle orifice (43) and the sixth throttle orifice (44). The fifth throttle orifice (43) and the sixth throttle orifice (44) are respectively connected to their lubrication components. The fifth branch is led out from the oil cooler (13), which is provided with a ninth throttling orifice (51). The rear end of the ninth throttling orifice (51) is connected to a seventh throttling orifice (54) and an eighth throttling orifice (55), which are respectively connected to their lubrication components.

3. The electric drive bridge flow adaptive system according to claim 2, characterized in that, A shuttle valve network is provided between the second branch, the third branch and the fourth branch, specifically including a first shuttle valve (25) and a second shuttle valve (35). The first shuttle valve (25) is connected to the rear end of the first pressure compensation valve (22) of the second branch, the first pressure compensation valve (22), the second pressure compensation valve (32), the third pressure compensation valve (42) and the second shuttle valve (35). The second shuttle valve (35) is connected to the rear end of the second pressure compensation valve (32) of the third branch and the rear end of the third pressure compensation valve (42) of the fourth branch.

4. The electric drive bridge flow adaptive system according to claim 3, characterized in that, The third branch and the fifth branch are connected, and a first check valve (52) is provided at the connection point. The fourth branch and the fifth branch are connected, and a second check valve (53) is provided at the connection point.

5. The electric drive bridge flow adaptive system according to claim 1, characterized in that, The oil cooler (13) is connected to bypass valves (12) at both ends.

Images