Double-oil-pump power assembly and double-pump communication control method
By using a dual oil-cooled motor parallel connection, a common oil chamber design, and intelligent control of a dual-pump connected oil circuit, the problem that a single oil-cooled motor in engineering machinery cannot meet the requirements of high torque and high power is solved, achieving efficient and reliable operation of the system and cost reduction.
Patent Information
- Application Number
- CN202610130562.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-30
- Publication Date
- 2026-03-17
AI Technical Summary
In existing construction machinery, a single oil-cooled motor cannot meet the requirements of high torque and high power, and the electric pump has a short service life, which causes the system to fail to work properly under harsh working conditions. Moreover, the replacement parts cycle is long, resulting in economic losses.
It adopts a dual oil-cooled motor parallel connection, common oil chamber design, dual pump connected oil circuit and intelligent control strategy. Pressure balance and flow compensation are achieved through dual electronic oil pump components and connected oil circuit to ensure normal operation of the system under abnormal conditions.
It improves the system's compactness, efficiency, and reliability, ensures sufficient cooling and lubrication flow under any operating conditions, reduces system costs and redundant design, and minimizes economic losses due to electric pump failure.
Smart Images
Figure CN121676675A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a powertrain, and more particularly to a dual-pump powertrain and a dual-pump connection control method. Background Technology
[0002] As construction machinery moves towards electrification, electric motors are replacing engines as the mainstream trend. However, construction machinery operates under complex conditions, with heavy-duty work being the norm, placing very high demands on electric motors. Currently, the following solutions are available on the market:
[0003] 1. Low-speed, high-torque motors directly replace engines. These motors are relatively large, mostly water-cooled, and are quite heavy. They also have low efficiency, low power density, and high cost.
[0004] 2. High-speed water-cooled motor with reducer: The motor is large, the efficiency is low, the power density is low, and the cost is high. At the same time, the reducer uses splash lubrication, which reduces the system efficiency.
[0005] 3. A high-speed oil-cooled motor reducer is matched with an electronic pump and an oil cooler. Under harsh working conditions, there is a risk of the electronic oil pump sucking into cavitation, which shortens the life of the electronic pump. A single electronic oil pump results in insufficient heat dissipation capacity of the assembly, which limits the overall power efficiency and torque. If the electronic pump fails or is damaged, the assembly will not be able to work, resulting in significant economic losses for the customer.
[0006] Based on the mature application and supply chain of oil-cooled motors in passenger vehicles, motors for construction machinery are also developing towards oil-cooled motors. However, a single oil-cooled motor cannot meet the high torque, high power, and continuous operation requirements of construction machinery, so a multi-motor parallel solution is adopted. Oil-cooled motors require electronic oil pumps to cool and lubricate the motor and powertrain. However, the lifespan of the electronic pump is the shortcoming of the entire powertrain. If one electronic pump fails, the entire powertrain cannot operate normally. At the same time, construction machinery work sites are often remote, and the replacement cycle of parts is long, which affects the use of construction machinery by customers and causes significant economic losses. Summary of the Invention
[0007] Purpose of the invention: The purpose of this invention is to propose a dual-oil-pump powertrain and a dual-pump interconnection control method. Through the parallel connection of two oil-cooled motors, a common oil chamber design, a dual-pump interconnection oil circuit, and an intelligent control strategy, the powertrain can achieve compact, efficient, and highly reliable operation.
[0008] Technical Solution: This invention includes a dual oil-cooled motor assembly, a reducer, a dual electronic oil pump assembly, and a connecting oil circuit; the dual oil-cooled motor assembly includes a first oil-cooled motor and a second oil-cooled motor arranged coaxially in parallel, each connected to both ends of the reducer's input shaft; the reducer and the dual oil-cooled motor assembly adopt a common oil chamber design; the dual electronic oil pump assembly includes an independently configured first electronic oil pump and a second electronic oil pump, providing cooling and lubrication oil circuits for the first and second oil-cooled motors respectively; the connecting oil circuit is used to connect the two cooling and lubrication oil circuits, realizing pressure balance under normal operating conditions and flow compensation under abnormal operating conditions.
[0009] The connecting oil circuit is either a middle connecting oil circuit or a bottom connecting oil circuit. The middle connecting oil circuit is connected to the middle section of the main oil circuit from the two electronic oil pumps to the motor, and the bottom connecting oil circuit is connected to the bottom of the branch oil circuit of the two electronic oil pumps.
[0010] In the common oil chamber of the dual oil-cooled motor assembly and the reducer, the return oil from the motor stator and rotor directly cools and lubricates the output bearing and output gear, achieving comprehensive cooling of the reducer shaft and gears in conjunction with active lubrication.
[0011] The cooling and lubrication circuit of the first electronic oil pump includes: cooling the stator of the first oil-cooled motor; cooling the rotor of the first oil-cooled motor; lubricating the motor bearings and the input shaft bearings of the reducer; cooling the intermediate gear of the motor; the cooling and lubrication circuit of the second electronic oil pump has the same structure as that of the first electronic oil pump.
[0012] Both the first and second oil-cooled motors are high-speed flat wire oil-cooled motors, employing a heat dissipation method of directly cooling the stator and rotor with oil.
[0013] The reducer includes an input shaft, an intermediate shaft, and an output shaft. The input shaft and the intermediate shaft are meshed by gears, and the intermediate shaft and the output shaft are meshed by gears to output the torque of the dual oil-cooled motor assembly in a coordinated manner.
[0014] A method for controlling the connection of two pumps in a dual-pump powertrain includes the following steps:
[0015] S1: Normal operating condition control, dual electronic oil pumps operate at the same speed and flow rate, and the pressure balance characteristics of the connected oil circuit ensure uniform flow of the two cooling and lubricating oil circuits;
[0016] S2: Real-time monitoring of the operating current of the dual electronic oil pumps. When the current deviation between the two sides is ≤20%, it is determined that there is slight suction on one side. The electronic oil pump on the side that has not suctioned air is controlled to increase its speed and compensate the flow rate of the suction side to the preset standard.
[0017] S3: When the current deviation between the two sides is greater than 20% and one side is completely emptied, the electric pump on the emptied side will operate according to the original requested state, while the electric pump on the non-emptied side will request the maximum speed.
[0018] In step S2, when the speed of the non-vacuum side electronic pump reaches its maximum value, it requests the maximum speed. After the state returns to normal, the speeds of the two electronic pumps are requested to remain the same.
[0019] In step S3, after detecting air suction or the fault condition is eliminated, the dual electronic oil pumps are controlled to resume operation at the same speed and flow rate.
[0020] The electronic oil pump uses the rate of change of current to help determine whether it is sucking in air or in a faulty state.
[0021] Beneficial effects: The present invention has the following advantages:
[0022] (1) The shared oil chamber design of the motor and reducer can not only simplify the design of the oil circuit and oil cooling system of the two motors and reducers, and reduce the design of the reducer oil cooling system, but also reduce the oil churning loss of the reducer and improve the system efficiency by 1-2%.
[0023] (2) The dual-pump interconnection scheme can not only meet the cooling and lubrication requirements under normal operating conditions, but also solve the problems of cavitation in single-pump schemes and insufficient cooling and lubrication flow of motors and reducers caused by cavitation in one side of the dual-pump disconnection scheme under extreme operating conditions such as uphill and downhill conditions above 30° and left and right inclines of 20°. The dual-pump interconnection scheme can at least ensure that one pump does not cavitate under any harsh operating conditions. Even if one pump cavits, the other pump can compensate for the cavitation oil circuit, ensuring that at least 70% of the flow from both pumps is provided for cooling and lubrication of motors and reducers on both sides. This effectively reduces the redundancy and over-design of the system and reduces system costs.
[0024] (3) During the design of the dual-pump connection scheme, the oil circuits on both sides are kept symmetrical. When working normally, the pressure of the connected oil circuits is balanced and convection will not be achieved. In abnormal working conditions such as cavitation, the oil circuit without cavitation will compensate for the cavitation or damage to the electronic pump oil circuit to keep the flow of the oil circuits on both sides uniform.
[0025] (4) The dual-pump control strategy of the dual-pump connection scheme can ensure no backflow under normal working conditions; under severe working conditions, a slight cavitation phenomenon occurs, and the two circuits can maintain the required flow rate; under severe working conditions, a cavitation phenomenon occurs, and the non-cavitation side oil pump is ensured to continue to operate at maximum capacity, ensuring that the system can provide the maximum flow rate under severe working conditions, so that the whole vehicle can maintain ultimate performance.
[0026] (5) The two high-speed oil-cooled motors are arranged coaxially, which reduces the torque required by a single motor, reduces the stack length of the motor, and reduces the outer diameter of the high-speed motor, effectively reducing the radial space of the motor. The system is more compact and helps with the overall vehicle layout.
[0027] (6) Construction machinery is often used in remote areas. If one oil pump fails, the motor will not work, the repair cycle will be long, causing delays in the customer's construction period and resulting in significant economic losses. Connecting the oil circuits of two electronic pumps can solve the problem of one electronic pump failing but still being able to work, effectively reducing the customer's losses. Attached Figure Description
[0028] Figure 1 This is a diagram of the three-in-one powertrain of the present invention;
[0029] Figure 2 This is a schematic diagram of the oil circuit for cooling and lubricating the first and second cooling motors, respectively.
[0030] Figure 3 This is a schematic diagram of an intermediate connecting oil circuit in a powertrain.
[0031] Figure 4 This is a schematic diagram of another type of bottom-connected oil circuit for the powertrain. Detailed Implementation
[0032] The invention will now be further described with reference to the accompanying drawings.
[0033] Example 1
[0034] like Figure 1 As shown, the dual oil pump powertrain of this embodiment includes a dual oil-cooled motor assembly, a reducer, a dual electronic oil pump assembly, and a connecting oil circuit. The dual oil-cooled motor assembly includes a first oil-cooled motor 1 and a second oil-cooled motor 2 arranged coaxially in parallel. The first oil-cooled motor 1 and the second oil-cooled motor 2 are two independent motors. The first oil-cooled motor 1 and the second oil-cooled motor 2 are respectively connected to both ends of the reducer input shaft through splines, keeping the two motors coaxial and outputting in parallel. The coaxial arrangement of the first oil-cooled motor 1 and the second oil-cooled motor 2 reduces the torque required by a single motor, lowers the motor stack length, and reduces the outer diameter of the high-speed motor, effectively reducing the radial space of the motor and making the system more compact, which is conducive to the overall vehicle layout.
[0035] Both the first oil-cooled motor 1 and the second oil-cooled motor 2 are high-speed flat wire oil-cooled motors. They adopt a heat dissipation method of direct oil cooling of the stator and rotor, which results in better motor heat dissipation, better continuous performance, improved electrical density, and reduced motor stack length, which can effectively reduce motor costs.
[0036] The reducer includes an input shaft 3, an intermediate shaft 4, and an output shaft 5. The input shaft 3 and the intermediate shaft 4 transmit torque through gear meshing, and the intermediate shaft 4 and the output shaft 5 also mesh through gear meshing to output the torque of the dual oil-cooled motor assembly in a coordinated manner. The reducer and the dual oil-cooled motor assembly adopt a common oil chamber design.
[0037] In the shared oil chamber of the dual oil-cooled motor assembly and the reducer, the return oil from the motor stator and rotor directly cools and lubricates the output bearings and output gears, achieving comprehensive cooling of the reducer shafts and gears in conjunction with active lubrication. This shared oil chamber design not only simplifies the oil circuit and oil cooling system design for both motors and the reducer, reducing the design requirements of the reducer's oil cooling system, but also minimizes oil churning losses in the reducer, improving system efficiency by 1-2%.
[0038] like Figure 2 As shown, the dual electronic oil pump assembly includes an independently configured first electronic oil pump 10 and a second electronic oil pump 11, which provide cooling and lubrication oil circuits for the first oil-cooled motor 1 and the second oil-cooled motor 2, respectively. The first electronic oil pump 10 provides cooling and lubrication for the first oil-cooled motor 1 through the first oil circuit 6, and the cooling and lubricating fluid flows out from the first outlet 12. The second electronic oil pump 11 provides cooling and lubrication for the second oil-cooled motor 2 through the second oil circuit 7, and the cooling and lubricating fluid flows out from the second outlet 13.
[0039] The cooling and lubrication circuit of the first electronic oil pump 10 is divided into four branches: Branch 1: cooling the stator of the first oil-cooled motor; Branch 2: cooling the rotor of the first oil-cooled motor; Branch 3: lubricating the motor bearings and the input shaft bearings of the reducer; Branch 4: cooling the intermediate gears of the motor. The cooling and lubrication circuit of the second electronic oil pump 11 has the same structure as that of the first electronic oil pump 10. The return oil from the motor stator and rotor directly cools and lubricates the output bearings and output gears; the reducer cools and lubricates the shaft gears through active lubrication and the return oil from the motor, reducing the traditional oil splash lubrication method.
[0040] The connecting oil circuit is used to connect the two cooling and lubrication oil circuits, achieving pressure balance under normal operating conditions and flow compensation under abnormal operating conditions for the dual pumps. The dual oil pump oil circuit connection scheme adopts a symmetrical design of oil circuits on both sides and motor to ensure oil circuit pressure balance and prevent convection. The connecting oil circuit is divided into a middle connecting oil circuit 8 and a bottom connecting oil circuit 9.
[0041] like Figure 3 As shown, the intermediate connecting oil circuit 8 is connected to the middle section of the main oil circuit from the two electronic oil pumps to the motor, realizing the connection between the first oil circuit 6 and the second oil circuit 7. Because the first oil circuit 6 and the second oil circuit 7 are symmetrical, it can ensure that the flow of the two oil circuits is normal when the two pumps work at the same time. When one electronic oil pump fails, the other electronic oil pump can provide cooling and lubrication to the two oil circuits. At the same time, the flow of the two oil circuits is evenly distributed, which can ensure that the assembly works normally under rated conditions.
[0042] like Figure 4As shown, the bottom connecting oil passage 9 is connected to the bottom of a branch oil passage leading from the two electronic oil pumps to the motor oil passage, thus connecting the first oil passage 6 and the second oil passage 7. Because the first oil passage 6 and the second oil passage 7 are basically symmetrical, the flow rate of the two oil passages can be guaranteed to be normal when both pumps are working simultaneously. When one electronic oil pump fails, the other electronic oil pump can provide cooling and lubrication to the two oil passages. The flow rate of the two oil passages can be basically evenly distributed, ensuring that the assembly can work normally under rated operating conditions.
[0043] The dual-pump interconnection scheme not only meets the cooling and lubrication requirements under normal operating conditions, but also solves the problems of cavitation in single-pump schemes and insufficient cooling and lubrication flow to the motor and reducer caused by cavitation in one pump under extreme conditions such as inclines above 30° and slopes of 20° to the left or right. This prevents damage and reduced product lifespan caused by cavitation in single-pump schemes and cavitation in dual-pump disconnection schemes. The dual-pump interconnection scheme can at least guarantee that one pump will not cavitate under any harsh operating conditions. Even if one pump cavits, the other pump can compensate for the cavitation flow, ensuring that at least 70% of the flow from both pumps is provided for cooling and lubrication of the motors and reducers on both sides. This effectively reduces system redundancy and over-design, and lowers system costs.
[0044] The dual-pump connection scheme is designed to maintain symmetry in the oil circuits on both sides. This ensures pressure balance in the connected oil circuits during normal operation, preventing convection. In abnormal conditions such as cavitation, the non-cavitating oil circuit compensates for cavitation or damage to the electronic pump, maintaining uniform flow on both sides. The dual-pump control strategy of this scheme ensures no backflow under normal operating conditions; in severe conditions with slight cavitation, it maintains the required flow rate in both circuits; and in severe conditions with cavitation, it ensures the non-cavitating pump continues to operate at maximum capacity, guaranteeing maximum flow rate under extreme conditions and maintaining optimal vehicle performance.
[0045] Example 2
[0046] The dual-pump interconnection control method of this embodiment includes the following steps:
[0047] S1. Under normal operating conditions, both pumps operate normally, and both pumps require the same speed and flow rate to ensure the balance of the two branches;
[0048] S2. When the machine is under harsh operating conditions, causing one side of the oil pump to suck in air, the load of the electric pump on the side sucking in air will decrease and the current will drop. If the current of one side of the electric pump is detected to be less than 20% different from that of the other side, the speed of the side without sucking in air will be increased to ensure that the flow on both sides reaches the original requested state. When the speed of the electric pump on the side without sucking in air reaches the maximum value, the maximum speed will be requested. When the state returns to normal, the speed of the electric pumps on both sides will be requested to be kept the same.
[0049] S3. When the machine is under severe operating conditions, causing one side of the oil pump to cavitate, if the current of one side's electric pump deviates by 20% compared to the other side, or if one side is completely cavitated, the electric pump on the cavitated side will operate according to its original requested state, while the electric pump on the non-cavitated side will request its maximum speed. This ensures that the oil circuits and motor flow on both sides reach their current maximum values, guaranteeing the vehicle's maximum performance to meet the most severe operating conditions. Once the situation returns to normal, the requested speeds of both electric pumps will remain the same.
Claims
1. A dual oil pump power assembly characterized by, The application relates to a double-oil-cooled motor assembly, a speed reducer, a double-electronic-oil-pump assembly and a communication oil path.
2. The dual oil pump power assembly of claim 1, wherein, The communication oil path is an intermediate communication oil path or a bottom communication oil path, the intermediate communication oil path is connected to the middle sections of the main oil paths of the two electronic oil pumps leading to the motors, and the bottom communication oil path is connected to the bottom sections of the branch oil paths of the two electronic oil pumps.
3. The dual oil pump power assembly of claim 1, wherein, The double-oil-cooled motor assembly and the speed reducer share an oil cavity, and the oil return of the motor stator and rotor directly cools and lubricates the output bearing and the output gear.
4. The dual oil pump power assembly of claim 1, wherein, The cooling and lubricating oil path of the first electronic oil pump comprises the following steps: cooling the first oil-cooled motor stator; cooling the first oil-cooled motor rotor; lubricating the motor bearing and the speed reducer input shaft bearing; and cooling the motor intermediate gear.
5. The dual oil pump power assembly of claim 1, wherein, The cooling and lubricating oil path of the second electronic oil pump is identical to that of the first electronic oil pump.
6. The dual oil pump power assembly of claim 1, wherein, The first oil-cooled motor and the second oil-cooled motor are both high-speed flat wire oil-cooled motors, and adopt the heat dissipation mode of directly cooling the stator and rotor with oil.
7. A method of controlling the communication between the two pumps of the dual-oil-pump power assembly according to any one of claims 1 to 6, characterized in that, The speed reducer comprises an input shaft, an intermediate shaft and an output shaft, the input shaft is meshed with the intermediate shaft through gears, and the intermediate shaft is meshed with the output shaft through gears. The application comprises the following steps: S1: normal working condition control, the double electronic oil pumps operate at the same rotating speed and flow rate, and the pressure balance characteristics of the communication oil path ensure that the flow rates of the two cooling and lubricating oil paths are uniform; S2: the working currents of the double electronic oil pumps are monitored in real time, when the current deviation between the two sides is less than or equal to 20%, it is determined that one side is slightly suctioned, the rotating speed of the electronic oil pump of the non-suction side is increased to compensate the flow rate of the suction side to a preset standard; 8. The dual-pump communication control method according to claim 7, wherein S3: when the current deviation between the two sides is greater than 20% to one side is completely suctioned, the electronic pump of the suction side operates according to the original request state, and the rotating speed request of the electronic pump of the non-suction side is the maximum value.
9. The dual-pump communication control method according to claim 7, wherein In step S2, when the rotating speed of the electronic pump of the non-suction side reaches the maximum value, the maximum rotating speed is requested, and when the state returns to normal, the rotating speed requests of the two electronic pumps remain the same.
10. The dual-pump communication control method according to claim 7, wherein In step S3, when the suction or fault state is monitored to be eliminated, the double electronic oil pumps are controlled to return to the same rotating speed and flow rate operation. The electronic oil pump determines the suction or fault state by the current change rate.