Stator oil-immersed motor structure for driving liquid cooling pump

Abstract

The invention belongs to the technical field of aviation electromechanical systems, and particularly relates to a stator oil immersion motor structure for driving a liquid cooling pump, which comprises a front end cover, a shell, a stator assembly, a rubber pad, an annular cover plate, a rear end cover, a stator sheath, a rear graphite bearing, an electric connector socket, a rotor assembly and a front graphite bearing, the front end cover, the stator assembly, the rear end cover, the rubber pad and the annular cover plate are fixed on the shell, the front graphite bearing and the rear graphite bearing are respectively fixed on the front end cover and the rear end cover, the front graphite bearing and the rear graphite bearing provide support for the rotor assembly, the front end cover and the rear end cover provide support for the stator sheath, and the electric connector socket is installed on the rear end cover. Sealing rings are arranged between the front end cover and the shell as well as between the front end cover and the stator sheath as well as between the rear end cover and the shell as well as between the rear end cover and the stator sheath, so that an environment where the stator assembly is located is constructed into a closed cavity; an oil port is formed in the portion, on the side wall of the closed cavity, of the shell, the closed cavity is filled with enough oil liquid, and the oil port is plugged through cooperation of a rubber pad and an annular cover plate.

Description

Technical Field

[0001] This invention belongs to the field of aviation electromechanical systems technology, specifically relating to a stator oil-immersed motor structure for driving a liquid-cooled pump. Background Technology

[0002] The function of a liquid-cooled pump is to drive the flow of conductive cooling medium in a closed loop. To meet the requirements of efficient heat dissipation and lightweight design of airborne equipment, liquid cooling systems play a crucial role in aerospace equipment. As a key power source for liquid cooling systems, the liquid-cooled pump ensures efficient heat transfer from the heat source to the heat dissipation device. With the development of high-performance aircraft and airborne electronic equipment, the demand for liquid-cooled pump motors is gradually increasing. The medium temperature can reach -55℃ to +70℃, and the coolant has conductive properties and high viscosity at low temperatures. Traditional liquid-cooled pumps use dynamic seals to prevent the medium from entering the motor body. However, the sealing cups used in dynamic seals have low reliability and short service life. Some liquid-cooled pump motors can be internally immersed in coolant, which solves the drawbacks of dynamic seals, but introduces new problems. Motors internally immersed in coolant must isolate the conductive equipment from the coolant. This is usually achieved by using a stator sleeve or epoxy potting to encapsulate the motor stator, thus isolating the stator from the coolant. Epoxy resin has a high coefficient of thermal expansion, poor thermal conductivity, complex processing, and poor maintainability. This often leads to the expansion of the potting compound and its squeezing of the stator sleeve when there are large temperature differences, resulting in the stator sleeve cracking, coolant leakage, or even motor burnout.

[0003] For stator-immersed oil motors used in liquid-cooled pump drives, traditional epoxy potting methods are insufficient to meet the motor's heat dissipation requirements. After stator potting, the internal temperature of the motor can reach 180℃ under rated operating conditions. The expansion coefficients of the potting compound and the sheath differ significantly between temperatures ranging from -55℃ to 180℃. Thermal expansion and contraction of the potting compound can cause the sheath to crack under pressure. Furthermore, the potting process is complex, inefficient, costly, and non-repairable, hindering motor heat dissipation and resulting in low reliability. For example, the structure disclosed in patent CN209389818U uses a stator sheath to separate the stator and rotor, providing good heat dissipation at the rotor while exposing the stator to air. However, this design is not conducive to stator heat dissipation and meets the requirements for motor miniaturization. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a stator-immersed oil motor structure for driving liquid-cooled pumps. This structure features a simple manufacturing process, convenient maintenance, efficient heat dissipation, high production efficiency, and high reliability.

[0005] The technical solution of the present invention is as follows: To achieve the above-mentioned objective, the present invention designs a stator oil-immersed motor structure for driving a liquid-cooled pump. The motor structure includes: a front end cover, a housing, a stator assembly, a rubber pad, an annular cover plate, a rear end cover, a stator sheath, a rear graphite bearing, an electrical connector socket, a rotor assembly, and a front graphite bearing. The front end cover, stator assembly, rear end cover, rubber pad, and annular cover plate are fixed to the housing. The front and rear graphite bearings are respectively fixed to the front and rear end covers, providing support for the rotor assembly. The front and rear end covers provide support for the stator sheath. The electrical connector socket is installed on the rear end cover. Sealing rings are provided between the front end cover and the housing and the stator sheath, as well as between the rear end cover and the housing and the stator sheath, constructing a closed cavity around the stator assembly. An oil port is opened on the side wall of the closed cavity of the housing. The closed cavity is filled with a sufficient amount of oil, and the oil port is sealed using the rubber pad and the annular cover plate.

[0006] Furthermore, the rotor assembly shaft has a central through-hole structure, and the front and rear graphite bearings have open slots. The internal flow channels enter the motor through the front graphite bearing, pass through the stator sleeve, the air gap between the rotor assembly and the rear graphite bearing, and then flow out through the central hole of the motor shaft, providing a cooling circuit for the motor.

[0007] Furthermore, the opening slots of the front graphite bearing and the rear graphite bearing are L-shaped and are respectively set on the bearing end face and the circumferential surface. There are multiple opening slots and they are evenly distributed around the circumference.

[0008] Furthermore, the stator assembly is formed by winding the stator core and enameled wire into an armature winding, then vacuum impregnating it with enamel and hot-pressing it into the housing. The outer circle of the stator assembly and the inner circle of the housing are interference fit.

[0009] Furthermore, the oil used is aviation lubricating oil or other electrical cooling oil.

[0010] Furthermore, the electrical connector socket is fixed to the rear cover by mounting screws, and the electrical connector socket has an oil-resistant sealing function.

[0011] Furthermore, the stator sheath is locally thickened at both ends to increase its strength.

[0012] Furthermore, the rubber pad is made of oil-resistant rubber and has a certain degree of ductility.

[0013] The technical effects of this invention are as follows: To improve the heat dissipation efficiency of the stator in a liquid-cooled pump motor and prevent the stator sheath from cracking due to high and low temperatures after potting, this invention fills the cavity containing the stator with oil and creates openings in the motor housing to facilitate oil filling. To accommodate pressure changes caused by the thermal expansion and contraction of the oil volume due to changes in high and low temperatures, a high-strength, oil-resistant rubber gasket is placed over the opening. This seals and buffers the pressure changes in the stator cavity caused by the thermal expansion and contraction of the oil, releasing pressure changes caused by temperature variations and preventing the stator sheath from deforming under stress, thus avoiding cracking. Furthermore, the motor structure designed using this invention achieves excellent heat dissipation within a minimal volume. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the motor of the present invention.

[0015] Figure 2 This is a schematic diagram of the motor stator sheath structure of the present invention.

[0016] Figure 3 This is a schematic diagram of the annular cover plate structure of the present invention.

[0017] Figure 4 This is a schematic diagram of the oil guide groove structure of the front and rear bearings.

[0018] The components are: 1. front end cover, 2. fixing screw, 3. sealing ring, 4. housing, 5. stator assembly, 6. rubber pad, 7. annular cover plate, 8. fixing screw, 9. sealing ring, 10. rear end cover, 11. fixing screw, 12. stator sleeve, 13. rear graphite bearing, 14. sealing ring, 15. electrical connector socket, 16. sealing ring, 17. rotor assembly, 18. sealing ring, and 19. front graphite bearing. Detailed Implementation

[0019] To make the implementation method of the present invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings.

[0020] like Figure 1As shown, this invention relates to a stator-immersed motor structure for driving a liquid-cooled pump, comprising: a front end cover 1, fixing screws 2, a sealing ring 3, a housing 4, a stator assembly 5, a rubber pad 6, an annular cover plate 7, fixing screws 8, a sealing ring 9, a rear end cover 10, fixing screws 11, a stator sheath 12, a rear graphite bearing 13, a sealing ring 14, an electrical connector socket 15, a sealing ring 16, a rotor assembly 17, a sealing ring 18, and a front graphite bearing 19; wherein the front end cover 1, the stator assembly 5, and the rear end cover... 10. Rubber pad 6 and annular cover plate 7 are fixed to the housing. Front graphite bearing 19 and rear graphite bearing 13 are fixed to front end cover 1 and rear end cover 10. Front graphite bearing 19 and rear graphite bearing 13 provide support for rotor assembly 17. Front end cover 1 and rear end cover 10 provide support for stator sleeve 12. Electrical connector socket 15 is installed on rear end cover 10. Front end cover 1, rear end cover 10, housing 4, stator assembly 5, annular cover plate 7 and electrical connector socket 15 are sealed by sealing rings.

[0021] In the motor structure designed above in this invention, the motor stator assembly is located within a cavity composed of a housing, end caps, and a stator sleeve. Aviation lubricating oil is filled into the cavity to facilitate motor heat dissipation and prevent motor burnout. The stator sleeve isolates the internal coolant from the aviation lubricating oil. The oil in the cavity containing the motor stator assembly experiences significant volume changes when there are large temperature differences. To prevent deformation of the sleeve due to these volume changes, an oil filler port is provided at the motor housing. This port is sealed with a high-strength, oil-resistant rubber gasket and secured with an annular cover. The rubber gasket has a certain degree of elasticity, allowing it to absorb pressure changes caused by volume variations in the oil due to high and low temperatures, while also providing a sealing function.

[0022] Meanwhile, considering the overall compact structure and heat dissipation performance, the motor shaft adopts a hollow shaft structure. The high-pressure coolant in the front cover of the motor flows into the motor through the oil guide groove on the motor bearing and between the stator and rotor air gap, so that the motor rotor is immersed in the coolant and flows out to the low-pressure area through the central through hole of the motor rotor, realizing the circulation of coolant inside the motor. The heat exchange between the inside and outside of the motor is achieved through the circulating coolant, which is used to dissipate heat from the motor.

[0023] When coolant enters the motor, the grease in traditional ball bearings is washed away under these conditions, rendering them ineffective and posing a risk of jamming. Therefore, graphite bearings, which can be lubricated by coolant, are used instead of ball bearings to ensure reliable operation even with coolant ingress. The bearing slots are L-shaped and located on the bearing end face and inner and outer walls; multiple slots are evenly distributed circumferentially. The rotor shaft has a through-hole structure, and the bearings have slots. Coolant dissipates heat from the motor stator sleeve, flowing into the motor through the front bearing slot, passing through the rotor assembly, and exiting through the central hole of the motor shaft, providing a cooling circuit for the motor.

[0024] Considering the specific application requirements, in the implementation of this invention, the permanent magnet of the motor is made of high-temperature resistant samarium cobalt magnet, which has a small reversible temperature coefficient, stable performance, and minimal change in magnetic properties after prolonged operation and heat generation, with a certain margin. In the stator design, the winding coils are made of oil-resistant polyester enameled round copper wire, and the stator impregnation varnish and slot insulation materials are made of oil-resistant and high-temperature resistant materials. The stator sheath is made of titanium alloy to isolate the stator cavity oil from the coolant, while simultaneously transferring heat for stator cooling. The ends of the stator sheath are locally thickened to increase strength. The annular cover plate is made of metal material, possessing a certain strength to achieve a sealing effect. The stator assembly is composed of electrical steel and copper windings, and the rotor assembly is composed of permanent magnets and stainless steel. The electrical steel and copper windings provide a rotating magnetic field for the motor, while the permanent magnets provide a constant magnetic field.

[0025] Sealing rings are used to seal the motor end cover with the housing, the end cover with the stator sleeve, and the end cover with the electrical connector socket, thus sealing the internal structure of the motor and preventing internal oil leakage that could reduce heat dissipation. The motor housing is a metal structure with a grease fitting on the side, which is sealed with a rubber gasket. The rubber gasket is an oil-resistant non-metallic structure with a certain degree of flexibility and sealing function, facilitating the release of internal pressure and preventing oil leakage. The electrical connector socket supplies power to the motor while preventing internal liquid leakage.

[0026] In some alternative implementations, the housing 4 is made of metal and has an oil filler port, which is sealed with a rubber gasket 6.

[0027] In some alternative implementations, the stator assembly 5 is interference-fitted onto the housing 4, and the stator assembly 5 and the stator sheath 12 are either clearance-fitted or transition-fitted.

[0028] In some alternative implementations, the stator assembly 4 is made of electrical steel and copper windings, and the rotor assembly 17 is made of permanent magnets and stainless steel. The electrical steel and copper windings of the stator assembly provide a rotating magnetic field for the motor, and the permanent magnets of the rotor assembly provide a constant magnetic field for the motor.

[0029] In some optional implementations, the shaft of the rotor assembly 17 has a central through-hole structure, and the front graphite bearing 19 and the rear graphite bearing 13 have open slots. The internal flow channels enter the motor through the front graphite bearing 19, pass through the stator sleeve 12, the air gap between the rotor assembly 17 and the rear graphite bearing 13, and then flow out through the central hole of the motor shaft, providing a cooling circuit for the motor.

[0030] In some alternative implementations, coolant is circulated inside the motor, aviation lubricating oil or other electrical cooling oil is circulated in the cavity where the stator assembly 4 is located, and the stator sleeve 12 is made of titanium alloy material to reduce losses, increase heat conduction capacity, and isolate the coolant from the oil.

[0031] In some alternative implementations, the annular cover 7 is made of aluminum alloy, and the rubber gasket 6 is fixed to the housing 4 to achieve a sealing effect.

[0032] In some alternative implementations, the electrical connector socket 15 supplies power to the motor while preventing leakage of internal liquids from the motor.

[0033] In some optional implementations, the opening slots of the front graphite bearing 19 and the rear graphite bearing 13 are L-shaped and are respectively set on the bearing end face and the circumferential surface. There are multiple opening slots and they are evenly distributed around the circumference.

[0034] In some optional implementations, rubber pad 6 is a high-strength oil-resistant rubber pad with certain oil resistance and ductility.

[0035] The specific working principle of the motor structure designed in this invention is as follows: The structure of the stator oil-immersed motor designed for driving liquid-cooled pumps is as follows: Figure 1 As shown, the stator assembly comprises: front cover 1, fixing screw 2, sealing ring 3, housing 4, stator assembly 5, rubber gasket 6, annular cover 7, fixing screw 8, sealing ring 9, rear cover 10, fixing screw 11, stator sleeve 12, rear graphite bearing 13, sealing ring 14, electrical connector socket 15, sealing ring 16, rotor assembly 17, sealing ring 18, and front graphite bearing 19. The stator retaining ring structure is as follows. Figure 2 As shown, the annular cover plate is as follows Figure 3 As shown, the bearing oil guide groove structure is as follows: Figure 4 As shown. The specific structure and assembly implementation are as follows: (1) The front cover 1 and the rear cover 10 are clearance fit with the housing 4 and are fixed by screws. A sealing ring is provided. The rubber gasket 6 is fixed to the housing 4 by the annular cover plate 7 and the fixing screws 8. The specific structure of the annular cover plate is as follows: Figure 3 As shown, the front graphite bearing 19 and the rear graphite bearing 13 are interference-fitted onto the bearing cavities of the front end cover 1 and the rear end cover 10. The specific structure of the motor is as follows. Figure 1 As shown,; (2) The electrical connector socket 15 is fixed to the rear cover 10 by mounting screws, and the electrical connector socket 15 has an oil-resistant sealing function; (3) The stator sleeve 12 and the inner circle of the stator assembly 5 are fitted with a clearance or transition fit. The stator sleeve 12 is fitted with the front end cover 1 and the rear end cover 10 with a clearance fit. The stator sleeve and the end cover are sealed by a sealing ring to isolate the oil and coolant. For the specific structure, see Figure 2 As shown; (4) The stator assembly 5 is made by winding the stator core and enameled wire into an armature winding, then vacuum impregnating it with enamel and hot-pressing it into the housing. The outer circle of the stator assembly 5 and the inner circle of the housing 4 are interference fit. (5) The motor shaft in rotor assembly 17 is a hollow shaft. This provides a channel for oil circulation; see the structure below. Figure 1 As shown; (6) The front graphite bearing 19 and the rear graphite bearing 13 are made of graphite, and open grooves are designed at their ends and around their circumference to provide lubrication. For details, see [link to specific structure]. Figure 4 As shown.

[0036] (7) The motor stator assembly 5 is located in a cavity consisting of a housing 4, a front end cover 1, a rear end cover 10, and a stator sheath 12, and aviation lubricating oil is poured into the cavity.

[0037] This invention aims to improve the heat dissipation efficiency of the stator in a liquid-cooled pump motor and prevent the stator sheath from cracking due to the inconsistency between the expansion and contraction of the potting compound and the sheath after high and low temperature encapsulation. The stator cavity is filled with oil, and an opening is made in the motor housing to facilitate oil filling. The oil serves to insulate, dissipate heat, and prevent sheath cracking. Because the oil itself is non-conductive, it can be used in the electrical structure of the stator. The thermal conductivity of the oil is higher than that of the potting compound, resulting in better heat dissipation and helping to reduce the motor size and increase power density. To accommodate pressure changes caused by the thermal expansion and contraction of the oil volume due to high and low temperature environments, a high-strength, oil-resistant rubber gasket is placed over the opening. This seals and buffers the pressure changes in the stator cavity caused by the thermal expansion and contraction of the oil, preventing the stator sheath from deforming and cracking due to pressure changes.

[0038] Traditional motors typically use a stator sleeve and epoxy resin potting to isolate the stator from the coolant. Epoxy resin has poor thermal conductivity and a high coefficient of thermal expansion. Under high and low temperature changes, the inconsistent deformation of the epoxy resin and the sleeve leads to stress deformation of the sleeve, causing stator sleeve cracking, coolant leakage, and even motor burnout. This invention uses oil filling at the stator and has openings in the housing for easy lubrication of the motor stator. Oil-resistant rubber gaskets are added at these openings to absorb oil pressure changes caused by temperature variations, preventing the stator sleeve from cracking due to stress deformation. Furthermore, the motor structure designed using this invention achieves excellent heat dissipation within a minimal size.

[0039] The specific processing and assembly methods of the motor mechanism designed in this invention may include the following specific implementation processes: In this invention, the motor housing 4 can be made of aluminum alloy for easy processing and weight reduction. The oil filler port can be placed on the housing 4 or the rear end cover 10. The stator sleeve 12 can be made of non-metallic materials (PEEK, CF) or titanium alloy (TC4) to reduce losses and increase heat conduction. The motor stator assembly 5 is located in a cavity composed of the housing 4, the front end cover 1, the rear end cover 10, and the stator sleeve 12. Aviation lubricating oil or other fluids can be poured into the cavity to improve heat conduction and facilitate the dissipation of heat from the motor. The stator assembly 5 is wound with mounting wires and connected to the electrical connector socket 15. The electrical connector socket 15 has an oil-resistant sealing function. The rubber gasket 6 is a high-strength, oil-resistant rubber gasket with a certain degree of extensibility, which facilitates the release of pressure generated by temperature differences in the aviation lubricating oil.

[0040] The above specific embodiments or examples are only used to explain the technical solutions of the present invention and are not intended to limit the present application. Parts not described in detail are considered to be conventional technical means or common knowledge in the field. It can be understood by those skilled in the art that, based on the design concept of the present application, the technical solutions described in the foregoing embodiments can be adapted or some or all of the technical features can be equivalently replaced. These modifications, equivalent replacements, and adaptive improvements do not depart from the technical essence of the present invention and should all be covered within the protection scope of the present application.

Claims

1. A stator-immersed oil motor structure for driving a liquid-cooled pump, characterized in that, The motor structure includes: a front cover, a housing, a stator assembly, a rubber pad, an annular cover plate, a rear cover, a stator sleeve, a rear graphite bearing, an electrical connector socket, a rotor assembly, and a front graphite bearing. The front cover, stator assembly, rear cover, rubber pad, and annular cover plate are fixed to the housing. The front and rear graphite bearings are fixed to the front and rear covers, respectively, providing support for the rotor assembly. The front and rear covers provide support for the stator sleeve. The electrical connector socket is installed on the rear cover. Sealing rings are provided between the front cover and the housing and stator sleeve, and between the rear cover and the housing and stator sleeve, creating a closed cavity for the stator assembly. An oil port is provided on the sidewall of the closed cavity of the housing. The closed cavity is filled with a sufficient amount of oil, and the oil port is sealed using the rubber pad and the annular cover plate.

2. The stator oil-immersed motor structure for driving a liquid-cooled pump as described in claim 1, characterized in that, The rotor assembly shaft has a central through-hole structure. The front and rear graphite bearings have open slots. The internal flow channels enter the motor through the front graphite bearing, pass through the stator sleeve, the air gap between the rotor assembly and the rear graphite bearing, and then flow out through the central hole of the motor shaft, providing a cooling circuit for the motor.

3. The stator oil-immersed motor structure for driving a liquid-cooled pump as described in claim 2, characterized in that, The front and rear graphite bearings have L-shaped opening slots, which are respectively set on the bearing end face and circumferential surface. There are multiple opening slots, which are evenly distributed around the circumference.

4. The stator oil-immersed motor structure for driving a liquid-cooled pump as described in claim 1, characterized in that, The stator assembly is made by winding the stator core and enameled wire into an armature winding, then vacuum impregnating it with enamel and hot-pressing it into the housing; the outer circle of the stator assembly and the inner circle of the housing are interference fit.

5. The stator oil-immersed motor structure for driving a liquid-cooled pump as described in claim 1, characterized in that, The fluid used is aviation lubricating oil or other electrical cooling oil.

6. The stator oil-immersed motor structure for driving a liquid-cooled pump as described in claim 1, characterized in that, The electrical connector socket is fixed to the rear cover by mounting screws, and the electrical connector socket has an oil-resistant sealing function.

7. The stator oil-immersed motor structure for driving a liquid-cooled pump as described in claim 1, characterized in that, The stator sheath is locally thickened at both ends.

8. The stator oil-immersed motor structure for driving a liquid-cooled pump as described in claim 1, characterized in that, The rubber pad is made of oil-resistant rubber and has a certain degree of ductility.

Images