Oil-cooled motor

Abstract

The present invention relates to an oil-cooled motor, comprising a casing, a stator core, a stator winding, a rotor core and a pressure plate arranged inside the casing; the stator winding is provided with a hole for cooling oil to circulate, and the hole forms an orifice on the inner circumferential surface of the stator winding; an oil baffle surface is relatively fixed at both ends of the axial direction of the rotor core, and the oil baffle surface faces the stator winding and is arranged around the circumference of the rotor core; the orifice of the hole on the inner circumferential surface of the stator winding is opposite to the oil baffle surface, and when observed from the axial cross-section of the motor, the oil baffle surface extends obliquely from the rotor core toward the stator winding side; by reasonably designing the two ends on the axis of the motor rotor core, the cooling oil can simultaneously cool the inside and outside of the winding at a very low cost, thereby better controlling the heat generation of the motor.

Description

Technical Field

[0001] The present invention relates to the field of motors, in particular to an oil-cooled motor for an automobile. Background Art

[0002] At present, with the development of new energy vehicle motors, higher and higher requirements are placed on the power density of motors, that is, higher requirements are placed on the speed and current of motors; in order to improve the power density of new energy vehicle motors, we need the speed of new energy vehicle motors to be as high as possible, the lighter the weight, the better, and the larger the current, the better; however, the higher the speed, the greater the iron loss, the greater the current, the higher the copper loss, and the higher the temperature rise of the motor; as the power density becomes higher and higher, the motor has the risk of excessive temperature rise leading to demagnetization of the magnet; therefore, as the power density of new energy vehicle motors develops towards higher and higher goals, higher requirements are placed on the thermal management design of the motor.

[0003] Water cooling is currently the mainstream heat dissipation method, but it cannot directly cool the heat source. Heat from the windings must pass through the insulation layer in the slots and the motor stator before being transferred to the casing and carried away by the water. This transfer path is long, the heat dissipation efficiency is low, and the fitting tolerances between the various components further affect the thermal resistance of the transfer path. Therefore, oil cooling technology, which has higher heat dissipation efficiency, has become a research hotspot. The advantages of oil cooling over water cooling are good insulation properties. The boiling and freezing points of oil are higher than those of water, making the coolant less likely to freeze at low temperatures and less likely to boil at high temperatures. Oil cooling is divided into direct oil cooling and indirect oil cooling. Direct oil cooling is further divided into oil immersion and oil spraying. The oil spraying cooling method sprays oil onto the stator end or other hot areas through an oil pump or other device for cooling. Although the design concept is to cool through spraying and oil throwing, the actual structural design is diverse. Slight structural changes inside the motor will produce significant differences in the heat dissipation effect, and at the same time have a significant impact on the motor's speed and working efficiency.

[0004] Currently, the common methods used by motor manufacturers are either to design complex rotor oil circuits and then use the centrifugal force of the rotor to spray the inside of the winding, or to arrange oil pipes to cool the outside of the winding. These methods require complex structural design of the motor interior and high design precision. Although these methods guarantee the heat dissipation effect of the motor to a certain extent, they come at a great cost in terms of motor efficiency and structural design.

[0005] Taking General Motors' U.S. patent (patent number: US8169110, patent name: Oil-cooled motor generator for automotive powertrain) as an example, this technical solution forms multiple oil paths through complex internal designs of the oil-cooled motor (such as C-channels and arc-shaped grooves in the balancing end plates), allowing the cooling oil to flow into the winding ends and contact the inner surface of the windings. However, the C-channels will cause a large amount of cooling oil to accumulate, increasing the operating burden of the motor and affecting the motor's efficiency. Although the balancing end plates set on the rotor core can send oil to the lower side, there are also problems with cooling the oil and obstructing the flow of oil. Overall, this design solution is complex in structure and places a heavy burden on the operating efficiency of the motor. Summary of the Invention

[0006] In response to the above problems, the present invention provides an oil-cooled motor. By rationally designing the two ends of the motor rotor core axis, the cooling oil can be cooled at a very low cost while cooling the inside and outside of the winding, thereby better controlling the heating of the motor.

[0007] An oil-cooled motor comprises a casing, a stator core, a stator winding, a rotor core and a pressure plate arranged inside the casing; the stator winding is provided with a hole for cooling oil to flow, and the hole forms an orifice on the inner circumference of the stator winding; it is characterized in that: oil baffles are relatively fixed at both ends of the rotor core in the axial direction, and the oil baffles face the stator winding and are arranged around the circumference of the rotor core; the orifice of the hole on the inner circumference of the stator winding is opposite to the oil baffle surface, and when observed from the axial cross-section of the motor, the oil baffle surface extends obliquely from the rotor core toward the stator winding side; thereby, the cooling oil flowing into the orifice of the hole on the inner circumference of the stator winding in the working state can be reflected by the oil baffle surface and then flushed to the inner circumference of the stator winding.

[0008] Preferably, the extended surface of the oil baffle surface intersects with the extended surface of the inner circumferential surface of the stator winding, so that the extended surface of the oil baffle surface envelops the end of the entire stator winding; to ensure that the cooling oil can contact the entire inner surface of the winding when flying out along the oil baffle plate, thereby improving the cooling effect.

[0009] Preferably, the pressure plate is fixedly arranged at both ends of the rotor core in the axial direction, and a circle of oil baffle is folded on the outer edge of the pressure plate, and the outer peripheral plate surface of the oil baffle serves as the oil baffle surface; in this preferred embodiment, the oil baffle is relatively fixed to the rotor core and rotates synchronously with the rotor core; the oil baffle surface is arranged on the pressure plate to achieve indirect relative fixation between the oil baffle surface and the rotor core.

[0010] The relevant contents of the present invention are explained as follows:

[0011] "An oil-blocking surface is relatively fixed at both ends of the rotor core in the axial direction": the relative fixation can include the oil-blocking surface being directly provided at both ends of the rotor core in the axial direction, and the oil-blocking surface and the rotor core are directly relatively fixed; or there can be other components between the two ends of the rotor core in the axial direction and the oil-blocking surface, and the component operates synchronously with the rotor core and the oil-blocking surface, and at this time the oil-blocking surface and the rotor core are indirectly relatively fixed.

[0012] Preferably, the projection of the oil-baffle surface on the axial section of the motor is a straight line segment; the oil-baffle surface of this shape is simple in design, convenient for processing and production, effectively reduces the difficulty of processing and assembly, and can ensure the oil-shedding effect.

[0013] As a further preference, the angle between the extended surface of the oil-blocking surface and the extended surface of the inner circumferential surface of the stator winding is a, and the angle a ranges from 0° to 30°.

[0014] Preferably, the projection of the oil retaining surface on the axial cross section of the motor is a concave curve, and the concave direction of the curve is toward the axis of the rotor core;

[0015] As a further preferred embodiment, the curve is a circular arc, an elliptical arc, or a parabolic arc;

[0016] Preferably, flow-gathering convex portions are further provided at both ends of the rotor core in the axial direction. The flow-gathering convex portions are located on the periphery of the oil-blocking surface. When observed on the axial cross-section of the motor, the length of the flow-gathering convex portions is shorter than the length of the oil-blocking surface. When the cooling oil is swung outward due to centrifugal force, the flow-gathering convex portions can block and disturb the cooling oil, causing the cooling oil to deflect from the direction of the centrifugal force and eventually be concentrated and swung toward the inner surface of the winding, thereby improving the cooling effect on the winding.

[0017] As a further preference, the surface of the spoiler protrusion facing the oil-blocking surface is parallel to the oil-blocking surface.

[0018] The beneficial effects of the present invention are as follows: the present invention forms a unique oil baffle structure by cleverly designing the two axial ends of the rotor core. The cooling oil coming out of the oil injection ring flows along the outer surface of the winding to the pores of the winding under the action of gravity, and then flows downstream to the oil baffle for temporary storage; the pressure plate that rotates synchronously with the rotor core generates a large centrifugal force when rotating at high speed, and the centrifugal force throws the cooling oil temporarily stored at the oil baffle surface to the inner circumference of the winding again, thereby better cooling the motor; the invention has very little internal modification to the cooling motor, effectively reducing the processing and modification costs, and at the same time will not excessively affect the working efficiency of the oil-cooled motor, and achieves simultaneous cooling of the inside and outside of the winding at a very small cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of an embodiment of the present invention.

[0020] Figure 2 Schematic diagram of the cross-sectional structure along the axial direction of the motor in one embodiment of the present invention.

[0021] Figure 3 Schematic diagram of the three-dimensional structure of a pressing plate in one embodiment of the present invention.

[0022] Figure 4 Schematic diagram of the cross-sectional structure of the pressure plate along the axial direction of the motor in one embodiment of the present invention.

[0023] Figure 5 The figure is a schematic diagram of the three-dimensional structure of the stator winding and the stator core in one embodiment of the present invention.

[0024] Figure 6 The figure is a schematic structural diagram of an oil retaining surface in an axial cross section of a motor in one embodiment of the present invention.

[0025] Figure 7 This is a schematic structural diagram of another oil retaining surface in the axial cross section of the motor in one embodiment of the present invention.

[0026] Figure 8 Schematic diagram of the flow path of cooling oil in one embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and beneficial effects of the present invention more clearly understood, the present invention is further explained and illustrated below through embodiments and drawings; the specific embodiments involved are only for explanation and are not intended to limit the scope of protection of the present invention.

[0028] Aiming at the technical problems of complicated oil circuit design and great difficulty in processing, manufacturing and assembling of existing oil-cooled motors, the present invention provides an oil-cooled motor, such as Figure 1-5 As shown, in one embodiment of the present invention, the oil-cooled motor includes a housing 1, a stator core 2 disposed inside the housing 1, a stator winding 6, a rotor core 3, a pressure plate 7, and an oil injection ring 4. The stator core 2 is sleeved on the outside of the rotor core 3, and a driving shaft 5 is provided on the central axis of the rotor core 3.

[0029] The stator winding 6 is exposed from both ends of the stator core 2; a wire slot is formed in the stator winding 6, and a stator coil is also wound on the stator winding 6; the rotor core includes coaxially stacked magnetic steel sheets; the oil injection ring 4 is connected to an oil pump disposed outside the housing 1, and cooling oil sprayed from the oil injection ring flows to the outer peripheral surface of the end of the stator winding 6 exposed from the stator core 2; the stator winding 6 is provided with pores 61 for facilitating the circulation of cooling oil, and the pores 61 are evenly spaced around the circumference of the stator winding 6; in this embodiment, the pores are channels extending radially along the rotor core, and the pores form orifices on the inner peripheral surface of the stator winding, and the orifices on the outer peripheral surface of the stator winding match the oil injection ring;

[0030] An oil baffle 81 is relatively fixed at both ends of the rotor core 3 in the axial direction, and the oil baffle 81 faces the stator winding 6 and is arranged around the circumference of the rotor core 3; the opening of the pore 61 on the inner circumference of the stator winding 6 is opposite to the oil baffle 81, and when observed from the axial cross-section of the motor, the oil baffle 81 extends obliquely from the rotor core 3 toward the stator winding side; thus, the cooling oil flowing into the opening of the pore 61 on the inner circumference of the stator winding 6 in the working state can be reflected by the oil baffle 81 and then flush the inner circumference of the stator winding 6; the flow path of the cooling oil can be as follows Figure 8 Indicated by the thick dashed line.

[0031] The relevant contents of the present invention are explained as follows:

[0032] Regarding the explanation of “an oil-blocking surface 81 is provided at both ends of the rotor core 3 in the axial direction, which is relatively fixed”: “relatively fixed” can include the oil-blocking surface 81 being directly provided at both ends of the rotor core 3 in the axial direction, in which case the oil-blocking surface 81 and the rotor core 3 are directly “relatively fixed”; or there can be other components between the two ends of the rotor core 3 in the axial direction and the oil-blocking surface 81, such as a pressure plate structure; this component operates synchronously with the rotor core 3 and the oil-blocking surface 81, in which case the oil-blocking surface 81 and the rotor core 3 are indirectly “relatively fixed”; whether directly relatively fixed or relatively fixed, it should be within the protection scope of “an oil-blocking surface 81 is provided at both ends of the rotor core 3 in the axial direction, which is relatively fixed” as stated in this case.

[0033] Taking indirect "relative fixation" as an example, in one embodiment of the present invention, the pressure plate 7 is fixedly arranged at both ends of the rotor core 3 in the axial direction; the pressure plate 7 is sleeved on the driving shaft 5 and rotates synchronously with the rotor core 3; the pressure plate 7 is in the shape of a ring plate, the inner edge of the pressure plate 7 faces the driving shaft 5, and the outer edge of the pressure plate 7 faces the stator winding 6; the outer edge of the pressure plate 7 is folded to one side to form a circle of oil baffle 8, and when observed from the axial cross section of the motor, the oil baffle 8 A folded angle is formed with the plate surface of the pressure plate 7, and the folded angle area can facilitate temporary storage of cooling oil; the axial extension line of the pore 61 passes through the oil baffle plate 8; the surface of the outer peripheral plate surface of the oil baffle plate 8 facing the pore 61 is called the oil baffle surface 81, and the oil baffle surface 81 is inclined toward the inner surface of the stator winding 6; in this embodiment, the extended surface of the oil baffle surface 81 intersects with the extended surface extending outward from the inner peripheral surface of the stator winding 6, so that the extended surface of the oil baffle surface 81 envelops the outer end of the stator winding 6, as shown in FIG. Figure 6 Or as shown by the dotted line in 7.

[0034] In this embodiment, the pressure plate 7 is folded to form a unique oil baffle structure. The cooling oil coming out of the oil injection ring 4 flows along the outer surface of the stator winding 6 to the pores 61 of the stator winding 6 under the action of gravity, and then flows downstream to the oil baffle surface 81 for temporary storage; the oil baffle surface 81 that rotates synchronously with the rotor core 3 generates a large centrifugal force when rotating at high speed, and this centrifugal force throws out the cooling oil temporarily stored in the oil baffle plate 8. In this embodiment, the cooling oil can cover the entire inner surface of the stator winding 6 when flying out along the oil baffle surface 81, so that the inner and outer surfaces of the stator winding 6 are cooled at the same time, thereby better cooling the motor; in this embodiment, only the unique oil baffle surface 81 needs to be designed. In this embodiment, the shape of the outer edge of the pressure plate 7 is adjusted, and the internal modification of the cooling motor is very small, which can effectively reduce the processing and modification costs. At the same time, it will not affect the working efficiency of the oil-cooled motor too much, and the simultaneous cooling of the inside and outside of the stator winding 6 is achieved at a very small cost.

[0035] like Figure 6 As shown, in one embodiment of the present invention, the projection of the oil baffle surface 81 on the axial cross-section of the motor is a straight line segment, and the oil baffle surface is a flat surface that is surrounded in a circle; the angle between the extended surface of the oil baffle surface 81 and the extended surface of the inner surface of the stator winding 6 is a, and the angle range of angle a is between 0-30°; the oil baffle plate 8 with a linear projection is simple and convenient to process, and is convenient for secondary discharge of the cooling oil; at the same time, the angle range of angle a is small, which further reduces the degree of bending of the oil baffle plate 8 during processing and reduces the processing difficulty.

[0036] When the oil-cooled motor is working, in order to ensure the cooling effect, the oil pump needs to provide sufficient oil supply. At this time, the amount of oil sprayed from the oil injection ring is large, so the cooling oil temporarily stored at the oil baffle becomes more; when there is too much cooling oil, it will affect the rotation speed of the rotor core, thereby reducing the working efficiency of the oil-cooled motor; for this reason, in one embodiment of the present invention, the rotor core 3 is further provided with a flow-gathering convex portion 9 at both ends in the axial direction, and the flow-gathering convex portion 9 is located on the periphery of the oil baffle surface 81, that is, the flow-gathering convex portion 9 is opposite to the oil baffle surface 81, and The flow-gathering protrusion 9 is parallel to the oil baffle surface 81; when observed on the axial cross-section of the motor, the length of the flow-gathering protrusion 9 is shorter than the length of the oil baffle surface 81; when the cooling oil is swung outward due to centrifugal force, the flow-gathering protrusion 9 can block and disturb the cooling oil, causing the cooling oil to deflect from the direction of the centrifugal force; especially when the amount of oil is large, the flow-gathering protrusion 9 can not only prevent the cooling oil from excessively accumulating in the oil baffle plate 8, but also make the cooling oil more concentrated and swung toward the inner surface of the stator winding 6, thereby improving the cooling effect on the stator winding 6.

[0037] In addition, the projection of the oil retaining surface 81 on the axial cross section of the motor is a concave curve, that is, the inwardly concave oil retaining surface 81 is surrounded in a circle; the concave direction of the curve is toward the axis of the rotor core 3, as shown in FIG. Figure 7 As shown; the curve is one of a circular arc, an elliptical arc, and a parabolic arc; the cooling oil flies out through the arc-shaped oil baffle surface 81, which can make the cooling oil spray more concentratedly onto the inner surface of the stator winding 6; at the same time, the arc-shaped oil baffle surface 81 can reduce the attenuation degree of the cooling oil speed when it flows down, so that the cooling oil can be thrown out again more smoothly, effectively increasing the flow speed of the cooling oil, thereby improving the cooling effect.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An oil-cooled motor comprising a housing, a stator core disposed within the housing, a stator winding, a rotor core, a pressure plate, and an oil spray ring; the stator winding is provided with a pore for circulating cooling oil, the pore forming an orifice on the inner circumference of the stator winding; and characterized in that: The pores are evenly distributed in the circumferential direction of the stator winding; the pores are channels extending radially along the rotor core, and the openings of the pores on the outer peripheral surface of the stator winding match an oil injection ring; oil baffles are relatively fixed at both ends of the axial direction of the rotor core, and the oil baffles face the stator winding and are arranged around the circumference of the rotor core; the pressure plate is fixed at both ends of the axial direction of the rotor core, and a circle of oil baffles is formed on the outer edge of the pressure plate, and the outer peripheral plate surface of the oil baffle serves as the oil baffle surface; the oil baffle and the pressure plate are fixed to each other. The surface forms an angle, and the angled area can facilitate the temporary storage of cooling oil; the opening of the pore on the inner circumferential surface of the stator winding is opposite to the oil baffle surface, and when observed from the axial cross-section of the motor, the oil baffle surface extends obliquely from the rotor core toward the stator winding side; the extended surface of the oil baffle surface intersects with the extended surface of the inner circumferential surface of the stator winding, so that the extended surface of the oil baffle surface envelops the end of the entire stator winding; in the working state, the cooling oil flowing into the opening of the pore on the inner circumferential surface of the stator winding can be reflected by the oil baffle surface and then flushed the inner circumferential surface of the stator winding; The rotor core is further provided with spoiler convex portions at both ends in the axial direction. The spoiler convex portions are located outside the oil baffle surface. When observed on the axial cross section of the motor, the length of the spoiler convex portions is shorter than the length of the oil baffle surface.

2. The oil-cooled motor according to claim 1, characterized in that: The projection of the oil-blocking surface on the axial section of the motor is a straight line segment, and the oil-blocking surface is a flat surface that surrounds the motor in a circle.

3. The oil-cooled motor according to claim 1, characterized in that: The angle between the extended surface of the oil-blocking surface and the extended surface of the inner surface of the stator winding is a, and the angle a range is between 0-30 degrees.

4. The oil-cooled motor according to claim 1, characterized in that: The projection of the oil-blocking surface on the axial cross section of the motor is a concave curve.

5. The oil-cooled motor according to claim 1, characterized in that: The surface of the spoiler protrusion facing the oil-blocking surface is parallel to the oil-blocking surface.

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