CN115899029A - An oil-cooled electric drive hydraulic system and its control method - Google Patents

Abstract

The invention relates to an oil-cooling electric drive hydraulic system, comprising: the first pump is connected with the main oil way and used for pumping oil to the main oil way; a main oil pressure control device for controlling the pressure in the main oil passage; the actuating element is connected with the pressure oil path and can execute corresponding operation according to the pressure in the pressure oil path; the hydraulic system further includes: and the second pump is connected with the lubricating oil way and is used for pumping the oil liquid to the lubricating oil way. According to the invention, the lubricating oil path is arranged, and the hydraulic system in the gearbox simultaneously cools and lubricates the gearbox and the driving motor, so that the gearbox is more integrated and lighter compared with the traditional water-cooled motor and gearbox. For water-cooling electric drive assembly, oil cold electric drive assembly can directly cool off the source that generates heat, and cooling efficiency is higher.

Description

An oil-cooled electric drive hydraulic system and its control method

technical field

The invention belongs to the technical field of vehicles, and in particular relates to an oil-cooled electric drive hydraulic system used in vehicles and a control method thereof.

Background technique

Electric vehicles have gained large-scale popularity, and their market share is gradually increasing. Many traditional automakers have also begun to gradually increase their investment in electric vehicles. At present, in pure electric vehicles at home and abroad, most of the electric drive devices used are the reducer structure with the drive motor matched with a fixed speed ratio. The cooling and lubrication inside the reducer is mainly through splash lubrication, while the drive motor is mostly through the design of water channels in the shell. Carry out water cooling and heat dissipation.

Contents of the invention

During the research and development of electric vehicles, the applicant found the following technical problems in the prior art:

1) The driving motor is matched with a single-speed reducer, which has strict requirements on the motor under high speed and high torque conditions. However, under the trend of high-speed motors, water-cooled motors cannot directly cool the heating elements, and the heat dissipation efficiency is low.

2) The drive motor needs to add additional water channels for heat dissipation, resulting in an increase in the volume and weight of the motor and complicating the assembly;

3) The driving motor and gearbox cooling are controlled separately, which increases the difficulty of control.

Combining the applicant's research and practical experience in this field, the following improved technical solutions are proposed here.

An oil-cooled electric drive hydraulic system, comprising:

The first pump is connected with the main oil circuit and is used to pump oil to the main oil circuit;

a main oil pressure control device, used to control the pressure in the main oil circuit;

The actuator is connected with the pressure oil circuit and can perform corresponding operations according to the pressure in the pressure oil circuit;

The hydraulic system also includes:

The second pump is connected to the lubricating oil circuit and is used to pump oil to the lubricating oil circuit.

According to an aspect of the present invention, the lubricating oil passage includes a plurality of branching oil passages of the lubricating oil passage.

According to one aspect of the present invention, an oil cooler and/or a one-way valve are arranged on at least one branch oil circuit.

According to one aspect of the present invention, a lubricating pressure relief valve is provided on the lubricating oil passage.

According to one aspect of the present invention, a temperature sensor is arranged on the lubricating oil path.

According to an aspect of the present invention, the first pump or the second pump is an electronic pump.

According to one aspect of the present invention, the main oil pressure control device includes an outlet port connected to the lubricating oil passage.

According to one aspect of the present invention, it further includes an actuator control valve, the inlet end of the actuator control valve is connected to the main oil circuit, and the outlet end is connected to the actuator.

According to one aspect of the present invention, a pilot oil circuit is further included, the pilot oil circuit is connected to the main oil circuit, and a pilot valve for the actuator control valve and/or the main oil pressure control device is arranged on the pilot oil circuit.

The present invention also proposes a control method for controlling the above-mentioned hydraulic system, which controls the pressure of the main oil circuit and the pressure oil circuit according to the driver's intention or the information fed back by the actual road conditions, and then controls the actuator;

The rotation speed of the second pump is controlled according to the cooling and lubrication flow required by the heating element at each rotation speed and torque and/or the external characteristics of the motor.

As can be seen from the above scheme, the present invention has the following advantages:

(1) By setting the lubricating oil circuit, the hydraulic system in the gearbox can cool and lubricate the gearbox and the drive motor at the same time, which is more integrated and lightweight than the traditional water-cooled motor plus gearbox.

(2) Compared with the water-cooled electric drive assembly, the oil-cooled electric drive assembly can directly cool the heat source, and the cooling efficiency is higher.

(3) The control of the electric drive assembly is more precise through the real-time feedback of the sensor, which can avoid the situation of insufficient supply or excessive supply, and is conducive to improving the efficiency of the whole machine

(4) The hydraulic system has comprehensive capabilities, simple control logic, and higher reliability during operation.

Description of drawings

Exemplary embodiments of the invention are described with reference to the accompanying drawings, in which:

Figure 1 shows a schematic diagram of the hydraulic system of the present invention.

Fig. 2 shows a control system diagram of the present invention.

Detailed ways

Embodiments of the present invention are described below with reference to the drawings. In the following description, numerous specific details are set forth in order to enable those skilled in the art to more fully understand and practice the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. Furthermore, it should be understood that the invention is not limited to the particular embodiments described. Rather, it is conceivable to implement the invention in any combination of the features and elements described below, regardless of whether they relate to different embodiments. Accordingly, the following aspects, features, embodiments and advantages are by way of illustration only and should not be considered as characteristics or limitations of the claims unless expressly stated in the claims.

The instructions about orientation that may be used in the following descriptions, such as "upper", "lower", "inner", "outer", "radial", "axial", etc., are only for convenience of description, unless otherwise specified, It is not intended to form any limitation on the technical solution of the invention. In addition, terms such as “first” and “second” are used hereinafter to describe elements of the present application, and these terms are only used to distinguish each element, and are not intended to limit the nature, sequence, order or number of these elements.

Figure 1 shows a schematic diagram of the hydraulic system of the present invention. In the hydraulic system shown in Figure 1, there are two pumps, respectively the first pump 3 and the second pump 4, the two pumps can be selected as electronic pumps, or other types of pumps, such as mechanical pumps . Both the first pump 3 and the second pump 4 pump oil from the oil tank 23 . In order to remove impurities in the oil, a first filter 1 is set between the first pump 3 and the oil tank 23, and a second filter 2 is set between the second pump 4 and the oil tank 23, thereby ensuring that the oil passing through the first pump 3 and the cleanliness of the oil pumped out by the second pump 4.

Further, the first pump 3 is set as a pressure pump, which is used to provide hydraulic oil with a certain pressure for the actuators in the subsequent oil circuit. The second pump 4 is set as a lubricating pump, which is used to provide cooling and lubricating oil for components in the subsequent oil circuit that need to be cooled and lubricated. The rotational speeds of the first pump 3 and the second pump 4 can be controlled by the electric drive control unit.

Specifically, a main oil pressure control valve 15 is provided after the first pump 3 . The oil passage between the first pump 3 and the main oil pressure control valve 15 serves as the main oil passage I. The main oil pressure control valve 15 has two inlet ports as well as an outlet port and a control port. The control end is connected to the main oil pressure pilot control valve 14, the main oil pressure pilot control valve 14 is a solenoid valve, the electric drive control unit can control the current supplied to the main oil pressure pilot control valve 14, and then control the main oil pressure pilot control valve 14 output pressure, thereby adjusting the pressure of the main oil pressure control valve 15, finally realizing the pressure control of the main oil circuit I.

Both the inlet end of the first pressure control valve 5 and the inlet end of the second pressure control valve 9 are connected to the main oil circuit I. On the main oil circuit I, a main oil circuit oil pressure sensor 22 is arranged to determine the oil pressure of the main oil circuit I. The outlet end of the first pressure control valve 5 is connected to the first actuator 8 , and the outlet end of the second pressure control valve 9 is connected to the second actuator 12 . In order to determine the pressure of the hydraulic oil supplied to the first actuator 8 , a first pressure sensor 7 is provided on the pipeline connected to the first actuator 8 . In order to determine the pressure of the hydraulic oil supplied to the second actuator 12 , a second pressure sensor 11 is provided on the pipeline connected to the second actuator 12 . The oil passage between the first actuator 8 and the first pressure control valve 5 can be referred to as the first pressure branch oil passage II, and the oil passage between the second actuator 12 and the second pressure control valve 9 can be referred to as The second pressure branch oil circuit III.

The first actuator 8 and the second actuator 12 may be clutches.

The first pressure control valve 5 is also provided with a control end, which is connected to the first pressure pilot control valve 6 . The first pressure pilot control valve 6 can control the first pressure control valve 5 through its output pressure. The second pressure control valve 9 is also provided with a control port which is connected to the second pressure pilot control valve 10 . The second pressure pilot control valve 10 can control the second pressure control valve 9 via its output pressure.

The first pressure control valve 5 and the second pressure control valve 9 may be mechanical valves. The first pressure pilot control valve 6 and the second pressure pilot control valve 10 can be solenoid valves, and the electric drive control unit is used to control the current supplied to the first pressure pilot control valve 6 and the second pressure pilot control valve 10, thereby controlling the pressure. .

A pressure relief valve 13 is also provided on the main oil passage I. The pressure reducing valve 13 can be a mechanical valve, and the rear end of the spool of the pressure reducing valve 13 is maintained at a target pressure lower than the main oil pressure by a preset value. The pressure reducing valve 13 is connected with the first pressure pilot control valve 6 , the second pressure pilot control valve 10 and the main oil pressure pilot control valve 14 through the pilot oil passage IV.

The main oil pressure control valve 15 can be replaced by an accumulator for maintaining pressure, and a flow control valve is used to adjust the pressure of the main oil circuit.

The outlet end of the main oil pressure control valve 15 may be called an overflow end, and this end is connected to the lubricating oil passage V. Specifically, the outlet end of the second pump 4 is connected to the lubricating oil passage, and the end of the lubricating oil passage is connected to the components to be lubricated, such as the gearbox 19 or the motor 20 . Thus, the second pump 4 pumps oil to the gearbox 19 or the motor 20 through the lubricating oil passage, thereby cooling and lubricating the components therein such as gears and stators. The lubricating oil circuit V can be divided into a plurality of branched oil circuits of the lubricating oil circuit, so as to lubricate different components to be lubricated. The flow between the branch oil circuits of each lubricating oil circuit can be regulated by a flow regulating device such as an orifice.

A lubricating pressure safety valve 16 is arranged on the lubricating oil road. A pressure filter 17 and an oil cooler 18 are provided in a lubricating oil circuit branch oil circuit for lubricating one of the components, for example, an oil circuit for lubricating the motor 20 . A non-return valve is also arranged in parallel with the pressure filter 17 .

A temperature sensor 21 is provided on the lubricating oil passage V to monitor the oil temperature of the lubricating oil passage V, and realize precise control of each component through real-time feedback.

The composition of the hydraulic system of the present invention has been described above. The working process of the hydraulic system will be described below in conjunction with the composition of the hydraulic system.

On the pressure side, the first pump 2 sucks oil from the oil tank 23 through the first filter 1 and supplies it to the main oil circuit I. Under the regulation of the main oil pressure control valve 15, the pressure reaches the target value, and the excess flow overflows to the lubricating oil Road V. At the same time, the main oil pressure sensor 22 can feed back the actual pressure of the main oil circuit to the electric drive control unit, and the electric drive control unit can adjust the oil pressure of the main oil circuit by adjusting the current of the main oil pressure pilot control valve 14 .

At the same time, the oil in the main oil circuit I flows to the pressure reducing valve 13. After the pressure is adjusted, it flows to the main oil pressure pilot control valve 14, the first pressure pilot control valve 6 and the second pressure pilot control valve 10 respectively. After adjustment, it is used to regulate the main oil pressure, the pressure of the first oil circuit and the pressure of the second oil circuit.

The oil in the main oil circuit I also flows to the first pressure control valve 5 and the second pressure control valve 9. The first pressure control valve 5 is in a normally closed state. Control command, the passage of the pressure control valve is opened, the oil enters the first pressure branch oil circuit II, and the first actuator 8 is controlled to work. At the same time, the first pressure sensor 7 can measure the real oil pressure in the first pressure branch oil circuit II Feedback to the electric drive control unit, the electric drive control unit can adjust the magnitude of the first pressure by adjusting the current of the first pressure pilot control valve. The same is true for the second pressure control valve 9 .

The second pump 4 sucks oil from the oil tank 23 through the first filter 2, and confluences with the flow overflowed from the main oil pressure control valve 15. After being filtered by the pressure filter 17 and cooled by the oil cooler 18, it is supplied to the transmission The heating element inside the box and the motor, the flow distribution ratio between the gearbox and the motor is adjusted by the flow regulating device, so that the supply flow can meet the needs of the gearbox and the motor at the same time, and the lubricating pressure safety valve 16 arranged on the lubricating oil circuit V will When the flow is too large, a part of the flow will be discharged back to the oil tank to prevent the efficiency of the motor and gearbox from being reduced due to over-lubrication. The temperature sensor 21 can feed back the oil temperature to the electric drive control unit in real time. The electric drive control unit can adjust the second The rotating speed of the pump 4 is used to adjust the size of the lubricating flow.

Fig. 2 shows a control system diagram of the present invention. Specifically, the specific control method of the pressure end of the hydraulic system is that the vehicle control unit sends demand commands to the electric drive control unit according to the driver's intention or the information fed back by the actual road conditions, and the electric drive control unit sends control to the pilot control valve according to the software calibration value. Current command, and then control the pressure of the main oil circuit, the first pressure branch oil circuit, and the second pressure branch oil circuit, prompting the actuator to complete a series of shifting actions to realize the current working condition requirements of the whole vehicle, and the feedback from the pressure sensor It can help the electric drive control unit to control more precisely, reduce energy consumption and improve efficiency.

At the lubricating end, the electric drive control unit sets the speed of the second pump according to the cooling and lubricating flow required by the heating element at each speed and torque and the external characteristics of the motor, and at the same time adjusts the speed according to the feedback value of the temperature sensor. Demand and supply, improve assembly efficiency.

What have been described above are merely exemplary embodiments pertaining to the spirit and principles of the invention. It will be apparent to those skilled in the art that various changes may be made to the examples described without departing from the spirit and principles described, and these changes and their various equivalents are envisioned by the inventor and fall within the scope of the present invention. within the scope defined by the claims of the present invention.

Claims (10)

1. An oil-cooled, electrically-driven hydraulic system comprising:

the first pump is connected with the main oil way and used for pumping oil to the main oil way;

a main oil pressure control device for controlling the pressure in the main oil passage;

the actuating element is connected with the pressure oil path and can execute corresponding operation according to the pressure in the pressure oil path;

characterized in that the hydraulic system further comprises:

and the second pump is connected with the lubricating oil way and used for pumping the oil to the lubricating oil way.

2. Oil-cooled electrically-driven hydraulic system according to claim 1,

the lubricating oil path comprises a plurality of lubricating oil path branch oil paths.

3. The oil-cooled electrically-driven hydraulic system according to claim 2,

and an oil cooler and/or a one-way valve is/are arranged on at least one branch oil path.

4. Oil-cooled electrically-driven hydraulic system according to any one of claims 1-3,

and a lubricating pressure safety valve is arranged on the lubricating oil pipeline.

5. The oil chiller drive hydraulic system of any of claims 1-3,

and a temperature sensor is arranged on the lubricating oil path.

6. The oil-cooled electrically-driven hydraulic system according to claim 5,

the first or second pump is an electronic pump.

7. Oil-cooled electrically-driven hydraulic system according to any one of claims 1-3,

the main oil pressure control device comprises an outlet end, and the outlet end is connected to the lubricating oil path.

8. The oil chiller drive hydraulic system of any of claims 1-3,

the hydraulic control system further comprises an actuating element control valve, wherein the inlet end of the actuating element control valve is connected to the main oil way, and the outlet end of the actuating element control valve is connected to the actuating element.

9. The oil-cooled electrically-driven hydraulic system according to claim 8,

the hydraulic control system further comprises a pilot oil way, wherein the pilot oil way is connected to the main oil way, and a pilot valve used for an actuating element control valve and/or a main oil pressure control device is arranged on the pilot oil way.

10. A control method for controlling an oil-cooled electrically-driven hydraulic system according to any one of claims 1-9,

controlling the pressure of the main oil way and the pressure oil way according to the intention of a driver or information fed back by actual road conditions, and further controlling an actuating mechanism;

the rotation speed of the second pump is controlled according to the cooling and lubricating flow rate required by the heating element and/or the external characteristic of the motor at each rotation speed and torque.

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