Cooling liquid storage device for bridge driving system and bridge driving system

Abstract

A cooling liquid storage device for a bridge driving system and a bridge driving system wherein the cooling liquid storage device (10) for a bridge driving system comprises: a cover plate (110) comprising a first cooling liquid inlet (111) and a second cooling liquid inlet (112); the cover plate (110) is connected to the shell (120) in a sealed mode to define a cooling liquid containing cavity, the first cooling liquid inlet (111) and the second cooling liquid inlet (112) are in fluid communication with the cooling liquid containing cavity, and the shell (120) is provided with a cooling liquid outlet (121); and a coolant pump (130) in fluid communication with the coolant outlet (121) of the housing (120).

Description

Coolant storage device for electric axle drive system and electric axle drive system Technical Field

[0001] The present invention relates to the field of vehicles, and more particularly to a coolant storage device for an electric axle drive system of a vehicle. Background Art

[0002] In existing designs, the coolant cavity is located at the bottom of the e-axle drive system and is completely open to the motor housing and transmission housing. Although the gears in the e-axle drive system are designed to use active lubrication, gear churning always occurs, which causes churning losses and reduces transmission efficiency.

[0003] When the vehicle is driving normally, the liquid level in the coolant chamber is higher than the gears used to generate oil churning lubrication and lower than the gap between the motor's rotor and stator. When the vehicle turns left or right, the e-axle drive system tilts left or right, toward the motor or transmission, causing the coolant in the coolant chamber to briefly enter the motor housing or transmission housing. Furthermore, the vehicle's motion can cause the coolant level to rise above the air gap between the motor's rotor and stator, causing rotor oil to fling, which affects motor efficiency. If the rotor flings oil, centrifugal force accelerates the coolant, increasing mechanical losses in the rotor.

[0004] When the vehicle is running normally, the liquid level in the coolant chamber is higher than the coolant pump inlet. When the vehicle accelerates or decelerates, or when the vehicle is going uphill or downhill, the liquid level in the coolant chamber may fall below the coolant pump inlet, causing insufficient coolant supply from the coolant pump, worsening NVH problems, and shortening the coolant pump's service life.

[0005] Therefore, a coolant reservoir for an electric axle drive system is needed that can reduce oil churning losses.

[0006] Summary of the Invention

[0007] One object of the present invention is to provide a coolant reservoir for an electric axle drive system and an electric axle drive system that can reduce oil churning losses. Another object of the present invention is to provide a coolant reservoir for an electric axle drive system and an electric axle drive system that can improve the efficiency of an electric motor. Another object of the present invention is to provide a coolant reservoir for an electric axle drive system and an electric axle drive system that can improve the efficiency of a transmission. Another object of the present invention is to provide a coolant reservoir for an electric axle drive system and an electric axle drive system that can reduce coolant pump fluid shortages.

[0008] One aspect of the present invention provides a coolant storage device for an electric bridge drive system, comprising: a cover plate including a first coolant inlet and a second coolant inlet; a housing, wherein the cover plate is sealingly connected to the housing to define a coolant receiving chamber, and the first coolant inlet and the second coolant inlet are respectively in fluid communication with the coolant receiving chamber, and the housing has a coolant outlet; and a coolant pump, which is in fluid communication with the coolant outlet of the housing.

[0009] According to some embodiments of the present invention, the coolant storage device further comprises a filter, wherein the filter is connected to an outlet of the coolant pump.

[0010] According to some embodiments of the present invention, the coolant pump and the filter are mounted to one axial side of the housing.

[0011] According to certain embodiments of the present invention, when viewed axially, the coolant containing chamber has an arcuate or inverted triangular cross-sectional shape in the housing, and the coolant outlet is arranged on an axial side of the housing close to the coolant pump and the filter, and is located at the top of the arc or the lower vertex of the inverted triangle.

[0012] According to some embodiments of the present invention, the housing includes a step portion located axially away from the coolant outlet, and the step portion is raised relative to the bottom of the housing.

[0013] According to some embodiments of the present invention, the cover plate and the housing are made of aluminum or plastic.

[0014] According to certain embodiments of the present invention, the coolant reservoir device is modularly designed into separate subassemblies, allowing for strong interchangeability. This modular design allows for adaptability to various e-bridge drive system configurations. This flexible adaptability can reduce R&D costs and time.

[0015] One aspect of the present invention provides an electric bridge drive system, comprising: an electric motor, including a motor housing defining a motor cavity; a transmission, including a transmission housing defining a transmission cavity; and a coolant storage device according to certain embodiments of the present invention, wherein a first coolant inlet of a cover plate of the coolant storage device is in fluid communication with the motor cavity, and a second coolant inlet is in fluid communication with the motor cavity and the transmission cavity.

[0016] According to some embodiments of the present invention, the coolant reservoir is mounted on the bottom of the motor housing.

[0017] According to some embodiments of the present invention, the first coolant inlet and the second coolant inlet of the cover plate of the coolant storage device are respectively arranged on both sides of the electric motor along the axial direction.

[0018] According to some embodiments of the present invention, the electric bridge drive system further includes a heat exchanger, wherein an outlet of the filter of the coolant storage device is fluidly connected to the heat exchanger.

[0019] According to certain embodiments of the present invention, because the coolant reservoir is designed as a separate subassembly, when the vehicle turns left or right, accelerates, decelerates, or drives uphill or downhill, the accelerated coolant flows into the coolant reservoir and strikes the inner surface of the cover and / or housing of the coolant reservoir. Consequently, the amount of coolant flowing back into the motor cavity and the transmission cavity can be reduced, thereby improving the efficiency of the motor and transmission. Since less coolant flows back from the coolant reservoir into the transmission cavity, the bottom of the transmission can remain dry, reducing gear churning losses, which can further improve the efficiency of the transmission. Furthermore, when the vehicle turns, the coolant does not enter the air gap between the stator and rotor of the motor, thereby reducing the impact on motor efficiency. According to certain embodiments of the present invention, the coolant level in the coolant reservoir will not be too high or too low, so the coolant inlet of the coolant pump will not be short of coolant, and the coolant pump will not experience insufficient supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a schematic diagram of a bridge driving system according to some embodiments of the present invention.

[0021] FIG. 2 is a schematic diagram of a bridge driving system according to some embodiments of the present invention from another angle.

[0022] FIG3 is an exploded schematic diagram of a bridge driving system according to some embodiments of the present invention.

[0023] FIG. 4 is a schematic diagram of a cooling liquid storage device according to some embodiments of the present invention.

[0024] FIG. 5 is a schematic diagram of a cover plate of a cooling liquid storage device according to some embodiments of the present invention.

[0025] 6 is a schematic diagram of a housing of a coolant storage device according to some embodiments of the present invention.

[0026] FIG. 7 is a schematic diagram of a housing of a cooling liquid storage device according to some embodiments of the present invention from another angle.

[0027] FIG8 is a schematic cross-sectional view of a cooling liquid storage device according to some embodiments of the present invention. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present invention are described with reference to the accompanying drawings. The following detailed description and the accompanying drawings are used to illustrate the principles of the present invention by way of example. The present invention is not limited to the preferred embodiments described, and the scope of the present invention is defined by the claims. The present invention will now be described in detail with reference to exemplary embodiments, some of which are illustrated in the accompanying drawings. The following description is made with reference to the accompanying drawings, and unless otherwise indicated, the same reference numerals in different drawings represent the same or similar elements. The schemes described in the following exemplary embodiments do not represent all schemes of the present invention. On the contrary, these schemes are merely examples of systems and methods of various aspects of the present invention involved in the appended claims.

[0029] The present invention provides a coolant storage device for an electric bridge drive system and an electric bridge drive system. Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the drawings illustrate only certain embodiments of the present invention, and the scope of the present invention should be determined based on the claims. As used herein, "axial" refers to the axial direction of the electric bridge drive system, which is parallel to the direction in which the drive shaft in the electric bridge drive system extends.

[0030] Figure 1 is a schematic diagram of a bridge drive system according to certain embodiments of the present invention. Figure 2 is a schematic diagram of a bridge drive system from another angle according to certain embodiments of the present invention. Figure 3 is an exploded schematic diagram of a bridge drive system according to certain embodiments of the present invention.

[0031] As shown in Figures 1 to 3, the electric bridge drive system includes a coolant reservoir 10, an electric motor 20, and a transmission 30. The electric motor 20 includes a motor housing 21. The motor housing 21 defines a cavity of the electric motor 20, i.e., a motor cavity. The transmission 30 includes a transmission housing 31. The transmission housing 31 defines a cavity of the transmission 30, i.e., a transmission cavity.

[0032] The coolant reservoir 10 is a separate reservoir for the electric bridge drive system. The coolant may be lubricating oil. According to certain embodiments of the present invention, as shown in FIG1 to FIG3 , the coolant reservoir 10 is mounted to the bottom of the housing 21 of the electric motor 20. In this document, the "bottom" of the electric motor 20 refers to the side of the electric motor 20 that is closer to the ground when the electric bridge drive system is installed in a vehicle. The coolant reservoir 10 can be mounted to the bottom of the electric motor 20 of the electric bridge drive system by bolts or the like. The coolant reservoir 10 and the electric motor 20 can be sealed by a gasket, glue, or the like.

[0033] The following describes a coolant storage device according to certain embodiments of the present invention with reference to the accompanying drawings. FIG4 is a schematic diagram of a coolant storage device according to certain embodiments of the present invention. The coolant storage device 10 includes a cover plate 110, a housing 120, a coolant pump 130, and a filter 140. FIG5 is a schematic diagram of a cover plate of a coolant storage device according to certain embodiments of the present invention. FIG6 is a schematic diagram of a housing of a coolant storage device according to certain embodiments of the present invention. FIG7 is a schematic diagram of the housing of a coolant storage device according to certain embodiments of the present invention from another angle. FIG8 is a schematic cross-sectional view of a coolant storage device according to certain embodiments of the present invention.

[0034] As shown in FIG5 , the cover plate 110 has a first coolant inlet 111 and a second coolant inlet 112. In an exemplary embodiment, as shown in FIG8 , the first coolant inlet 111 and the second coolant inlet 112 are respectively axially disposed on either side of the motor 20. Specifically, the first coolant inlet 111 is disposed on a side of the motor 20 away from the transmission 30, and the second coolant inlet 112 is disposed on a side of the motor 20 closer to the transmission 30. The first coolant inlet 111 is in fluid communication with the motor cavity of the motor 20. The second coolant inlet 112 is in fluid communication with the motor cavity of the motor 20 and the transmission cavity of the transmission 30. According to certain embodiments of the present invention, the cover plate 110 may be made of aluminum or plastic, and the plastic may be glass fiber reinforced PBT plastic, such as PBT+GF30.

[0035] According to certain embodiments of the present invention, the cover plate 110 is sealingly connected to the housing 120. The cover plate 110 and the housing 120 define a coolant storage chamber of the coolant storage device 10. When the cover plate 110 is connected to the housing 120, the first coolant inlet 111 and the second coolant inlet 112 are respectively in fluid communication with the coolant storage chamber. The cover plate 110 and the housing 120 may be connected by bolts or the like. The cover plate 110 and the housing 120 may be sealed by a gasket or adhesive. According to certain embodiments of the present invention, the housing 120 may be made of aluminum or plastic, and the plastic may be glass fiber reinforced PBT plastic, such as PBT+GF30.

[0036] According to certain embodiments of the present invention, as shown in FIG4 , the coolant pump 130 and the filter 140 are mounted to the housing 120, preferably on one axial side of the housing 120. The housing 120 has a coolant outlet 121, as shown in FIG7 . The coolant outlet 121 is disposed on one axial side of the housing 120 near the coolant pump 130 and the filter 140. In an exemplary embodiment, the coolant outlet 121 of the housing 120 is located at the lowest point of the coolant chamber. The coolant outlet 121 fluidically connects the coolant chamber within the housing 120 with the coolant pump 130, which is located outside the housing 120. Thus, the coolant pump 130 can pump coolant out of the coolant chamber through the coolant outlet 121. The filter 140 is connected to the outlet of the coolant pump 130. Thus, the coolant pumped by the coolant pump 130 can be filtered by the filter 140. In an exemplary embodiment, as shown in FIG6 and FIG7 , the housing 120 includes a step 122 located on a side away from the coolant outlet 121. The step portion 122 is raised relative to the bottom of the housing 120. Thus, when the vehicle turns, the step portion 122 can buffer the accelerated coolant in the coolant receiving chamber.

[0037] In some embodiments, the cover plate 110 is generally flat, and the connection portion of the housing 120 to the cover plate 110 is generally coplanar. Thus, the coolant receiving chamber of the coolant storage device 10 is located within the housing 120. In some embodiments, the coolant receiving chamber within the housing 120 has a generally arcuate or inverted triangular cross-sectional shape when viewed axially. In this case, the coolant outlet 121 can be positioned at the apex of the arc or the lower vertex of the inverted triangle, thereby being located at the lowest point of the coolant receiving chamber.

[0038] In an exemplary embodiment, as shown in FIG2 , the electric bridge drive system further includes a heat exchanger 40. The coolant storage device 10 further includes a filtered coolant outlet 141. In some embodiments, the filtered coolant outlet 141 is connected to the coolant inlet of the heat exchanger 40 via a hose.

[0039] According to an embodiment of the present invention, the coolant has two return paths in the electric bridge drive system. On the side away from the transmission 30, as shown in Figure 8, the coolant in the motor cavity flows into the coolant holding chamber of the coolant storage device 10 through the first coolant inlet 111 and is sucked away by the coolant pump 130 through the coolant outlet 121. On the side close to the transmission 30, as shown in Figure 8, the coolant in the transmission cavity and the coolant in the motor cavity flow into the coolant holding chamber of the coolant storage device 10 through the second coolant inlet 112, flow within the coolant storage device 10 to the coolant outlet 121, and are sucked away by the coolant pump 130 through the coolant outlet 121. The coolant sucked away from the coolant outlet 121 by the coolant pump 130 is then filtered by the filter 140. The coolant filtered by the filter 140 can flow to the heat exchanger 40 through a hose.

[0040] According to certain embodiments of the present invention, the coolant reservoir 10 is designed as a separate subassembly and preferably comes pre-installed with a coolant pump 130 and a filter 140. The separate reservoir is modularly designed as a subassembly, making it highly interchangeable. The modular design of the coolant reservoir can be adapted to different e-bridge drive system architectures. The coolant reservoir's flexible adaptability can reduce R&D costs and time.

[0041] According to certain embodiments of the present invention, because the coolant reservoir 10 is designed as a separate subassembly, when the vehicle turns left or right, accelerates or decelerates, or drives uphill or downhill, the accelerated coolant flows into the coolant reservoir 10 and strikes the inner surface of the cover 110 and / or housing 120 of the coolant reservoir 10. This reduces the amount of coolant flowing back into the motor and transmission cavities, improving the efficiency of the motor and transmission. Since less coolant flows back from the coolant reservoir into the transmission cavity, the bottom of the transmission remains dry, reducing gear churning losses, which further improves transmission efficiency. Furthermore, when the vehicle turns, coolant does not enter the air gap between the stator and rotor of the motor, thereby minimizing the impact on motor efficiency. According to certain embodiments of the present invention, the coolant level in the coolant reservoir does not become excessively high or low, preventing a lack of coolant at the coolant pump's coolant inlet and preventing the coolant pump from experiencing insufficient supply.

[0042] According to certain embodiments of the present invention, a separate coolant reservoir can be flexibly used for oil cooling system verification tests, such as oil quantity, static and dynamic oil levels, oil pump calibration, etc. These verification tests can be performed using only the coolant reservoir as a subassembly, without requiring the entire e-axle drive system, thereby saving verification cost and time.

[0043] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the configurations and methods of the above-described embodiments. On the contrary, the present invention is intended to cover various modifications and equivalent configurations. In addition, although the various elements and method steps of the disclosed invention are shown in various exemplary combinations and configurations, other combinations including more or fewer elements or methods also fall within the scope of the present invention.

[0044] Reference Signs List

[0045] 10 coolant storage device;

[0046] 20 electric motors;

[0047] 21 motor housing;

[0048] 30 transmission;

[0049] 31 transmission housing;

[0050] 40 heat exchanger;

[0051] 110 cover plate;

[0052] 111 first coolant inlet;

[0053] 112 second coolant inlet;

[0054] 120 shell;

[0055] 121 coolant outlet;

[0056] 122 steps;

[0057] 130 coolant pump;

[0058] 140 filters;

[0059] 141 Filter coolant outlet.

Claims

1. A cooling liquid storage device (10) for an electric bridge drive system, comprising: A cover plate (110) comprising a first coolant inlet (111) and a second coolant inlet (112); A housing (120), wherein the cover plate (110) is sealingly connected to the housing (120) to define a cooling liquid receiving chamber, and the first cooling liquid inlet (111) and the second cooling liquid inlet (112) are respectively in fluid communication with the cooling liquid receiving chamber, and the housing (120) has a cooling liquid outlet (121); and A coolant pump (130) is in fluid communication with the coolant outlet (121) of the housing (120).

2. The coolant storage device (10) according to claim 1, further comprising a filter (140), wherein: The filter (140) is connected to an outlet of the coolant pump (130).

3. The coolant storage device (10) according to claim 2, wherein: The coolant pump (130) and the filter (140) are mounted on one axial side of the housing (120).

4. The cooling liquid storage device (10) according to claim 3, wherein: When viewed along the axial direction, the cooling liquid receiving chamber has an arcuate or inverted triangular cross-sectional shape in the housing (120), and The coolant outlet (121) is arranged in the housing (120) on one axial side close to the coolant pump (130) and the filter (140), and is located at the top of the arc or the lower vertex of the inverted triangle.

5. The cooling liquid storage device (10) according to claim 4, wherein: The housing (120) comprises a step portion (122) located at a side away from the coolant outlet (121) in the axial direction, and the step portion (122) is raised relative to the bottom of the housing (120).

6. The cooling liquid storage device (10) according to claim 5, wherein: The cover plate (110) and the housing (120) are made of aluminum or plastic.

7. A bridge drive system, comprising: An electric motor (20) comprising a motor housing (21) defining a motor cavity; A transmission (30) comprising a transmission housing (31) defining a transmission cavity; and A coolant storage device (10) according to any one of claims 3 to 6, wherein a first coolant inlet (111) of a cover plate (110) of the coolant storage device is in fluid communication with the motor cavity, and a second coolant inlet (112) is in fluid communication with the motor cavity and the transmission cavity.

8. The electric bridge drive system according to claim 7, wherein: The coolant storage device (10) is installed at the bottom of the motor housing (21).

9. The electric bridge drive system according to claim 8, wherein: The first coolant inlet (111) and the second coolant inlet (112) of the cover plate (110) of the coolant storage device (10) are respectively arranged on both sides of the motor (20) along the axial direction.

10. The electric bridge drive system according to claim 9, further comprising a heat exchanger (40), wherein: The outlet of the filter (140) of the coolant storage device (10) is fluidly connected to the heat exchanger (40).

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