A motor cooling flow rate testing system and method

Abstract

The application discloses a motor cooling flow test system and method, wherein the system comprises: a differential output shaft connected with a differential of a reverse traction motor and an electric drive assembly; four oil guide hoses led out from four oil collecting cavities formed after a split flow stator is matched with a main body sheath and a rotor shaft; the four oil guide hoses are introduced into four sub-oil tanks of a four-equal-part oil tank; an electronic oil pump is still installed at the original position of the shell of the electric drive assembly; oil in an oil pool is connected to the inlet of the electronic oil pump through an external pipeline and then is input into a motor cavity; and a flow meter is connected in series on the pipeline between the electronic oil pump and the oil pool. The technical content disclosed by the application can measure the cooling oil flow of the stator, winding and rotor shaft oil throwing of the motor under limited equipment conditions in the design verification stage, can provide direct and effective measurement data for the structural parameter optimization design of the oil channel system of the electric drive assembly, and can reduce the risk of overheating failure caused by unreasonable design.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and more specifically, to a system and method for testing motor cooling flow rate. Background Technology

[0002] With the increasing sales of electric vehicles in the Chinese market, most domestic OEMs have also begun research and development on three-in-one electric drive assemblies. High-power motors generate a large amount of heat during operation, causing a sharp rise in the internal temperature of the motor, which can lead to risks such as magnet demagnetization, reduced efficiency, and failure of winding insulation and bearings. Therefore, the heat dissipation design of high-power motors is a very important aspect, as this design directly affects the safety, reliability, and functionality of the electric drive system.

[0003] Currently, the mainstream methods for motor temperature control are water cooling and oil cooling, with oil cooling gradually gaining an advantage. However, when electric drive assemblies are used in vehicles, it is impossible to measure and control the highest temperature point within the motor windings in real time. But in practical applications, a motor temperature rise simulation model can be established and corrected using measured data to predict the motor's temperature rise. The key lies in the actual flow rate of the stator, windings, and rotor.

[0004] Existing technical solutions:

[0005] 1) Currently, most three-in-one (digital motor, reducer, controller) electric drive oil-cooled motors have the following characteristics in their cooling scheme structure: they use a single electronic pump as the total cooling and lubrication flow source for the electric drive assembly. An oil passage system is set up inside the housing wall, and the oil passage parameters determine the flow distribution to meet the flow requirements of each point. The cooling oil passages of the stator and windings reach the oil spray ring through numerous circumferentially distributed axial oil passages on the outer edge of the stator. Finally, the winding ends are sprayed with cooling oil through multiple circumferentially distributed holes on the oil spray ring. The rotor shaft is designed to be hollow, and several circumferentially distributed through holes are set at the axial positions corresponding to the two ends of the windings. The cooling oil distributed from the housing oil passages can cool the rotor when it passes through the hollow rotor shaft. When the rotor rotates, the cooling oil in the hollow shaft is thrown out and hits the inner side of the winding ends for end cooling. In addition, the oil passage system is designed with some corresponding bearing active lubrication holes and gear active lubrication holes.

[0006] Disadvantages of existing technology:

[0007] The design of the oil passage system for the three-in-one electric drive assembly includes corresponding active lubrication holes for bearings and gears, as well as clearance for oil guide pipes, numerous axially distributed oil passages on the outer edge of the stator, and factors such as oil slinging caused by the centrifugal force of the rotor rotation, all of which affect the simulation and prediction accuracy of the oil passage system. Furthermore, the internal space of the electric drive assembly is limited, and the total pressure drop of the oil passages is relatively small, making it difficult to directly measure the actual cooling flow of the stator, windings, and rotor by directly installing flow measurement devices.

[0008] Therefore, how to provide a motor cooling flow test system and method has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0009] The purpose of this invention is to provide a system and method for testing motor cooling flow rate.

[0010] According to a first aspect of the present invention, a motor cooling flow rate testing system is provided, comprising an oil sump, an electronic oil pump, a flow meter, a reverse-drive motor, a shunt stator, an oil guide hose, and a four-part oil tank;

[0011] The reverse drive motor is connected to the differential output shaft of the electric drive assembly; four oil guide hoses are led out from the four oil collection chambers formed by the combination of the split stator, the main casing, and the rotor shaft, and introduced into the four sub-tanks of the four-equal oil tank; the electronic oil pump is still installed in the original position of the electric drive assembly housing; the oil in the oil sump is led to the inlet of the electronic oil pump through an external pipeline, and then input into the motor cavity; the flow meter is connected in series on the pipeline between the electronic oil pump and the oil sump.

[0012] Optionally, an oil inlet is opened on the upper side of the bottom of the main body shell, and the oil in the oil tank is connected to the inlet of the electronic oil pump through an external pipe and input into the motor cavity through the oil inlet; the oil inlet hole of the electronic oil pump on the original main body shell is sealed with a solid plastic tube.

[0013] Optionally, the four-part oil tank is installed above the oil pool at a first predefined height; the main body shell is installed above the four-part oil tank at a second predefined height.

[0014] Optionally, the first predefined height is greater than 100mm.

[0015] Optionally, the structure of the split stator is as follows: the original rotor is incorporated into the stator to form a split stator, the winding slots on the stator are removed, and all oil passage structural features are retained;

[0016] The shunt stator and rotor shaft are clearance-fitted.

[0017] Optionally, the system further includes: a cover plate;

[0018] The cover plates are installed at both ends of the shunt stator and sealant is applied to the mating surfaces. A through hole is opened at the bottom of the cover plate and a corresponding connector is installed, and the oil guide hose is connected to it.

[0019] According to a second aspect of the present invention, a method for testing motor cooling flow rate is provided, comprising the motor cooling flow rate testing system described in any one of the first aspects of the present invention, the specific steps of which include: step S1, starting the electronic oil pump and controlling the flow rate into the main body casing of the main oil passage by adjusting the speed of the electronic oil pump, and controlling the rotor shaft speed of the reverse drive motor control electric drive assembly; when it is necessary to measure the stator, winding oil spraying amount and rotor oil throwing amount, actively controlling the electronic oil pump to start working, at which time the liquid level of the four sub-tanks of the four-equal-divided oil tank begins to rise, when the liquid level of the highest tank exceeds the third predefined height, actively controlling the electronic oil pump to shut it off, and simultaneously recording the liquid level height of the four sub-tanks and the time to reach the liquid level height;

[0020] Step S2: Calculate the volume of oil in the four sub-tanks based on the liquid level height of the four sub-tanks; calculate the flow rate of oil in each sub-tank based on the volume of oil in the four sub-tanks and the corresponding time.

[0021] Optionally, the method further includes:

[0022] Step S3: Repeat steps S1 and S2 under different predefined measurement conditions to complete the flow measurement under various predefined measurement conditions.

[0023] Optionally, the third predefined height is 3 / 5 of the total height of the sub-tank.

[0024] According to the technical content disclosed in this invention, the following beneficial effects are achieved: under limited equipment conditions, during the design verification stage, the cooling oil flow rate of the stator, windings and rotor shaft of the motor can be measured, providing direct and effective measurement data for the optimization design of the oil passage system structural parameters of the electric drive assembly, and reducing the risk of overheating failure due to unreasonable design.

[0025] Under limited equipment conditions, during the formulation and optimization stage of motor temperature rise control strategy, the provided cooling oil flow data of motor stator, winding, and rotor oil slinging, and the correction of the motor temperature rise calculation model are more in line with the characteristics of this product. This allows for the formulation of a more reasonable control strategy, reduces the risk of electric drive assembly failure due to overheating, and improves the safety, reliability, and competitiveness of the product.

[0026] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0028] Figure 1This is a schematic diagram of a motor cooling flow rate testing system according to an embodiment;

[0029] Figure 2 This is a schematic diagram of a shunt stator structure provided according to an embodiment;

[0030] Figure 3 This is a schematic diagram of the main body shell structure provided according to an embodiment.

[0031] Explanation of reference numerals in the attached drawings: 1-oil sump, 2-electronic oil pump, 3-flow meter, 4-reverse drive motor, 5-rotor shaft, 6-main body casing, 7-diverter stator, 8-cover plate, 9-oil guide hose, 10-four-part oil tank. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0033] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0034] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0035] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0037] According to a first aspect of the invention, such as Figures 1-3 As shown, a motor cooling flow test system is provided, including an oil sump 1, an electronic oil pump 2, a flow meter 3, a reverse drive motor 4, a split stator 7, an oil guide hose 9, and a four-part oil tank 10.

[0038] The reverse drive motor 4 is connected to the differential output shaft of the electric drive assembly to provide rotational power to the system; four oil guide hoses 9 are led out from the four oil collection chambers formed by the shunt stator 7, the main casing 6, and the rotor shaft 5, and introduced into the four sub-tanks of the four-part oil tank 10; the electronic oil pump 2 is still installed in the original position of the electric drive assembly housing; the oil in the oil sump 1 is led to the inlet of the electronic oil pump 2 through an external pipe, and then input into the motor cavity; the flow meter 3 is connected in series on the pipe between the electronic oil pump 2 and the oil sump 1.

[0039] In some embodiments, an external oil tank 1 is used, which contains about 20L of oil. According to the temperature requirements of the measured working conditions, the oil in the container can be heated. The heating method can be a heating method that generates heat by passing an electric resistance wire or a heating chamber heating method.

[0040] In some embodiments, an oil inlet is provided on the upper side of the bottom of the main body shell 6, and the oil in the oil tank 1 is connected to the inlet of the electronic oil pump 2 through an external pipe and input into the motor cavity through the oil inlet; the oil inlet hole of the electronic oil pump on the original main body shell 6 is sealed with a solid plastic tube.

[0041] Specifically, the oil return hole between the reducer cavity and the motor cavity, including the oil return channel at the bottom, is eliminated to prevent oil from flowing between the two cavities and affecting the measurement; an oil passage is designed at the bottom of each end of the main body shell 6 to allow the cooling flow at both ends of the two windings to be measured.

[0042] In order to ensure that the oil inside the main casing flows out to the four-part oil tank in a timely and smooth manner, and that the oil in the four-part oil tank can be drained smoothly, certain requirements need to be placed on the installation position and height of the main casing 6, the four-part oil tank 10, and the oil pool 1: the four-part oil tank 10 is installed above the oil pool 1 at a predetermined height; the main casing 6 is installed above the four-part oil tank 10 at a predetermined height.

[0043] To ensure the oil flows out quickly and smoothly and prevents stagnation, the predefined height is greater than 100mm.

[0044] The structure of the shunt stator 7 is as follows: the original rotor is incorporated into the stator to form a shunt stator, the winding slots on the stator are removed, and all oil passage structural features are retained;

[0045] The shunt stator 7 and the rotor shaft 5 are in clearance fit, and the rotor shaft can still rotate freely.

[0046] Specifically, by designing and analyzing the oil passages inside the motor, the main flow routes of the cooling oil were determined, and four oil flow routes were identified. Therefore, the original stator can be structurally modified and combined with the main casing and rotor shaft to form four oil collection chambers.

[0047] The system also includes: a cover plate 8;

[0048] The cover plates 8 are installed at both ends of the shunt stator 7 and sealant is applied to the mating surfaces. A through hole is opened at the bottom of the cover plate 8 and a corresponding connector is installed, and the oil guide hose 9 is connected to it.

[0049] According to a second aspect of the present invention, a method for testing motor cooling flow rate is provided, comprising the motor cooling flow rate testing system described in any one of Embodiment 1, wherein the specific steps include:

[0050] Step S1: Start the rotation speed of the electronic oil pump 2 to control the flow rate of the main oil passage into the main casing 6, and control the rotor shaft speed of the reverse drive motor to control the electric drive assembly; when it is necessary to measure the stator, winding oil spraying amount and rotor oil throwing amount, actively control the electronic oil pump 2 to start working. At this time, the liquid level of the four sub-tanks of the four-equal-divided oil tank 10 begins to rise. When the liquid level of the highest tank exceeds the predefined height, actively control the electronic oil pump 2 to shut it off, and record the liquid level height of the four sub-tanks and the time to reach the liquid level height.

[0051] Step S2: Calculate the volume of oil in the four sub-tanks based on the liquid level height. Calculate the flow rate of oil in each sub-tank based on the oil volume and the corresponding time. The flow rate is given by q = V / t. For example, if the oil volume in oil tank 1 is V1 = 6L and the recording time is t = 60s, then the corresponding flow rate for oil tank 1 is q = 6L / 60s = 0.1L / s. The flow rates of the other tanks are measured similarly. Because the motor cooling oil flowing out becomes a free fluid, and the flow meter itself has significant liquid resistance, it is not suitable for measurement.

[0052] Step S3: Repeat steps S1 and S2 under different predefined measurement conditions to complete the flow measurement under various predefined measurement conditions.

[0053] In some embodiments, the predefined height is 3 / 5 of the total height of the sub-tank. If the liquid level is too low, it will affect the measurement accuracy; if the liquid level is too high, there is a risk of overflow.

[0054] In summary, the technical content disclosed in this invention enables the measurement of cooling oil flow rates in the stator, windings, and rotor shafts of a motor during the design verification phase, under limited equipment conditions. This provides direct and effective measurement data for optimizing the structural parameters of the oil passage system of the electric drive assembly, reducing the risk of overheating failure due to unreasonable design. Furthermore, under limited equipment conditions, during the motor temperature rise control strategy formulation and optimization phase, the provided cooling oil flow rate data for the stator, windings, and rotor shafts, along with the correction of the motor temperature rise calculation model, better suits the characteristics of this product. This allows for the formulation of more reasonable control strategies, reducing the risk of overheating failure of the electric drive assembly and improving the product's safety, reliability, and competitiveness.

[0055] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A motor cooling flow rate testing system, characterized in that, include: Oil sump, electronic oil pump, flow meter, reverse drag motor, distributor stator, oil guide hose and four-part oil tank; The reverse drive motor is connected to the differential output shaft of the electric drive assembly; four oil guide hoses are led out from the four oil collection chambers formed by the coupling of the stator, the main casing, and the rotor shaft, and introduced into the four sub-tanks of the four-equal-division oil tank; the electronic oil pump is installed on the housing of the electric drive assembly; the oil in the oil sump is led to the inlet of the electronic oil pump through an external pipe, and then input into the motor cavity; the flow meter is connected in series on the pipe between the electronic oil pump and the oil sump; An oil inlet is opened on the upper side of the bottom of the main body shell, and the oil in the oil tank is led to the inlet of the electronic oil pump through an external pipe and then input into the motor cavity through the oil inlet; the oil inlet hole of the electronic oil pump on the original main body shell is sealed with a solid plastic tube; The four-part oil tank is installed at a first predefined height position above the oil pool; the main body shell is installed at a second predefined height position above the four-part oil tank. The first predefined height is greater than 100mm; The structure of the shunt stator includes: incorporating the rotor into the stator to form a shunt stator; The shunt stator and rotor shaft are fitted with a clearance. The system also includes: a cover plate; The cover plates are installed at both ends of the shunt stator and sealant is applied to the mating surfaces. A through hole is opened at the bottom of the cover plate and a corresponding connector is installed, and the oil guide hose is connected to it.

2. A method for testing motor cooling flow rate, characterized in that, The motor cooling flow rate testing system as described in claim 1 includes the following specific steps: Step S1: Start the electronic oil pump and control the flow rate of the main oil passage into the main casing by the rotation speed of the electronic oil pump, and control the rotor shaft speed of the reverse drive motor to control the electric drive assembly; when it is necessary to measure the stator, winding oil spraying amount and rotor oil throwing amount, actively control the electronic oil pump to start working. At this time, the liquid level of the four sub-tanks of the four-equal-divided oil tank begins to rise. When the liquid level of the highest tank exceeds the third predefined height, actively control the electronic oil pump to shut it down, and record the liquid level height of the four sub-tanks and the time to reach the liquid level height. Step S2: Calculate the volume of oil in the four sub-tanks based on the liquid level height of the four sub-tanks; calculate the flow rate of oil in each sub-tank based on the volume of oil in the four sub-tanks and the corresponding time.

3. The method for testing motor cooling flow rate according to claim 2, characterized in that, The method further includes: Step S3: Repeat steps S1 and S2 under different measurement conditions to complete the flow measurement under various measurement conditions.

4. The method for testing motor cooling flow rate according to claim 2, characterized in that, The third predefined height is 3 / 5 of the total height of the sub-tank.

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