Spiral oil feed hollow motor shaft

Abstract

The application discloses a hollow motor shaft with spiral oil supply, and the non-driving end of the motor shaft is provided with a flow increasing valve; the flow increasing valve is in the shape of a ring, and a plurality of spiral radial grooves are formed on the inner surface of the flow increasing valve; a plurality of oil outlet holes are arranged on the cross section of the motor shaft perpendicular to the axial direction, the through holes of the oil outlet holes are inclined and do not pass through the shaft center of the motor shaft, and the plurality of oil outlet holes on the same section of the motor shaft are in the shape of a ring to spray oil in the self-rotating state. The application adds a component, i.e. the flow increasing valve, at the non-driving end of the motor shaft, the inner surface of the flow increasing valve is in the shape of a horn mouth to radiate oil columns, the surface area is larger, and the cooling effect is better; meanwhile, the oil outlet holes of the hollow motor shaft are designed to be inclined and do not pass through the shaft center of the motor shaft, the oil outlet flow rate is faster, the circulation is faster, and the oil accumulation in the inner cavity is less.

Description

Technical Field

[0001] This invention belongs to the automotive field, and specifically relates to a spiral oil supply hollow motor shaft. Background Technology

[0002] Smaller and lighter motors are the inevitable path for motor development today. Therefore, the pursuit of power density and torque density is a long-term trend. However, under the impact of the EV industry, the demand for motor density, efficiency, and other technical indicators is accelerating rapidly. Previous gradual technological development can no longer meet the needs of the main system. In this environment, various technical means need to be maximized to improve power density, including: updated electromagnetic design, better electromagnetic materials, and of course, better thermal management. The power limit of a motor is often limited by its temperature rise limit; therefore, improving the motor's cooling capacity can immediately increase power density. On the other hand, with the popularization of permanent magnet motors, while enjoying their advantages, we must also tolerate their shortcomings—"the performance of permanent magnet motors degrades with increasing temperature." Therefore, to prevent reversible and irreversible demagnetization of permanent magnets, a low-temperature rotor environment is always desired; low operating temperature is the best strategy for extending the lifespan of permanent magnets and insulating materials. This crucial responsibility inevitably falls on thermal management technology.

[0003] Logically, water cooling of the motor housing should meet most needs, so why does oil cooling technology continue to emerge? There are two reasons: one is the shortcomings of liquid cooling. This cooling method requires the heat source inside the motor to be transferred to the outside through layers of materials and then carried away by water channels. For example, the windings inside the motor coils. Due to thermal resistance, a temperature gradient exists from the windings to the water-cooled housing. The windings cannot be directly cooled, leading to heat buildup and the formation of localized hot spots. Therefore, direct cooling of the heat source is needed to improve cooling efficiency. Oil, due to its locally non-magnetic and non-conductive properties, has no effect on the motor's magnetic circuit, thus oil is chosen as the medium for direct internal cooling.

[0004] However, existing oil cooling systems have the following drawbacks: a small amount of cooling oil remains inside the shaft, affecting the dynamic balance of the motor shaft; the cooling oil is columnar, resulting in a small contact area and low heat exchange rate; and the cooling oil circulation speed is low, leading to poor cooling effect. Oil-cooled shafts have very low initial oil supply velocity, relying mainly on the motor shaft's rotation to drive the cooling oil, which is then ejected from the oil outlet or flows out by gravity. Furthermore, the oil supply nozzle has been upgraded from static to dynamic, requiring an additional power source and increasing the complexity of the equipment.

[0005] Purpose of the invention

[0006] The purpose of this invention is to improve the oil cooling effect and provide a spiral oil-feeding hollow motor shaft.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a spiral oil-feeding hollow motor shaft, wherein a flow-increasing valve is provided at the non-drive end of the motor shaft, the flow-increasing valve is annular, and the inner surface of the flow-increasing valve has several spiral radial grooves; several oil outlet holes are provided on the cross section of the motor shaft perpendicular to the axial direction, the through holes of the oil outlet holes are inclined and do not pass through the axis of the motor shaft, and the several oil outlet holes on the same cross section of the motor shaft spray oil in an annular shape when the motor shaft is rotating.

[0008] Furthermore, the outer ring of the flow booster valve is interference-fitted with the inner diameter of the motor shaft.

[0009] Furthermore, the groove on the inner surface of the flow booster valve is funnel-shaped, and the diameter of the oil inlet end is smaller than that of the oil outlet end.

[0010] Furthermore, the number of grooves is the same as or equal to the number of oil outlet holes on the cross-section of the motor shaft, or is 2 or 3 times the number of oil outlet holes.

[0011] Furthermore, the number of grooves is 6 to 12.

[0012] Furthermore, the number of grooves is 8.

[0013] Furthermore, the grooves are symmetrically radial, with a single-sided expansion angle of 3°.

[0014] Furthermore, the inner surface of the oil inlet end of the flow booster valve has a groove wall arc angle ≤ 1 / 3 of the groove arc angle.

[0015] Furthermore, multiple sets of oil outlet holes are provided along the motor shaft, and these multiple sets of oil outlet holes are evenly distributed along the motor shaft at equal intervals in the axial direction and at equal angles in the radial direction.

[0016] Furthermore, the position of the flow booster valve is set so that the movement trajectory of the cooling oil through the flow booster valve conforms to the Archimedean spiral curve, the oil outlet is located on the Archimedean spiral curve, and the direction is the same as the tangent direction of the curve.

[0017] This invention adds a component—a flow booster valve—to the non-drive end of the motor shaft. The inner surface of the flow booster valve is flared to radiate oil columns, resulting in a larger surface area and better cooling effect. At the same time, the oil outlet of the hollow motor shaft is designed to be inclined and does not pass through the axis of the motor shaft, resulting in a faster oil flow rate, faster circulation, and less oil accumulation in the inner cavity. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of the hollow motor shaft in the spiral oil supply embodiment.

[0019] Figure 2 This is a partial schematic diagram of the flow booster valve in an embodiment.

[0020] Figure 3 This is a schematic diagram of an Archimedes spiral in an embodiment. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product or device.

[0023] like Figure 1 The hollow spiral oil supply motor shaft shown has an additional component—a flow booster valve 2—added to the non-drive end of motor shaft 1. The flow booster valve is generally annular, and its outer ring is interference-fitted with the inner diameter of the shaft. Figure 2 As shown, the inner surface of the flow booster valve has multiple spiral radial grooves (flared opening: small at the oil inlet and large at the oil outlet) 3. The number of grooves is 1 (equal), 2, or 3 times the number of oil outlet holes on the cross-section of the motor shaft, with 6-12 grooves, and 8 being optimal. The grooves are symmetrically radial, and the optimal single-sided expansion angle is 3°.

[0024] Oil inlet end of the inner surface of the flow booster valve: The angle of the raised groove wall arc is 4 ≤ the angle of the groove arc × 1 / 3. Taking 8 grooves and an expansion of 3° as an example: the circumference is divided into 8 equal parts, each part is 45°; the groove wall of the oil inlet end is 11.25°, the groove is 33.75°, the groove wall of the oil outlet end is 5.25°, and the groove is 39.75°.

[0025] Because it needs to cooperate with other components, the oil outlet position is fixed and perpendicular to the pipe wall, and it cannot be tilted axially (from the drive end to the non-drive end). Therefore, the oil outlet 5 is designed with the oil outlet through hole tilted (e.g., Figure 3 The oil outlet hole's diameter is perpendicular to the motor shaft's axis, but does not pass through it; it is inclined.

[0026] When the motor shaft is rotating, multiple oil outlets (a group) on the same cross section spray oil in a circular pattern, and the axial tilt design does not exceed the range of the aforementioned circular pattern.

[0027] Multiple sets of oil outlet holes can be arranged axially on the motor shaft. For ease of manufacturing and assembly, these oil outlet holes are evenly spaced axially and uniformly distributed radially at equal angles. Based on the known positions of the oil outlet holes, the origin is deduced using the Archimedes' spiral formula to find a suitable and stable trajectory for the cooling oil movement, thus identifying the optimal solution path with the most uniform distribution and minimal interference.

[0028] Install a flow booster valve at a suitable position on the non-drive end of the motor shaft along the optimal solution path. The flow booster valve's spiral curve 6 represents the optimal solution. Drill holes along the radial tangent direction at the intersection of each oil outlet hole and the inner wall of the motor shaft, forming the aforementioned inclined oil outlet holes (e.g., Figure 3 ).

[0029] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hollow motor shaft for spiral oil supply, characterized in that: A flow booster valve is provided at the non-drive end of the motor shaft. The flow booster valve is annular in shape, and its inner surface has several spiral radial grooves. Several oil outlet holes are provided on the cross-section of the motor shaft perpendicular to the axial direction. The through holes of the oil outlet holes are inclined and do not pass through the axis of the motor shaft. When the motor shaft is rotating, the several oil outlet holes on the same cross-section spray oil in an annular pattern. The outer ring of the flow booster valve is interference-fitted with the inner diameter of the motor shaft. The grooves on the inner surface of the flow booster valve are funnel-shaped, and the diameter of the oil inlet end is smaller than that of the oil outlet end. The arc angle of the groove wall on the inner surface of the oil inlet end of the flow booster valve is ≤1 / 3 of the arc angle of the groove. The position of the flow booster valve is set so that the movement trajectory of the cooling oil through the flow booster valve conforms to the Archimedean spiral curve. The oil outlet hole is located on the Archimedean spiral curve, and its direction is the same as the tangent direction of the curve.

2. The spiral oil-feeding hollow motor shaft according to claim 1, characterized in that: The number of grooves is the same as or equal to the number of oil outlet holes on the cross-section of the motor shaft, or is 2 or 3 times the number of oil outlet holes.

3. The spiral oil-feeding hollow motor shaft according to claim 1, characterized in that: The number of grooves is 6 to 12.

4. The spiral oil-feeding hollow motor shaft according to claim 1, characterized in that: The number of grooves is 8.

5. The spiral oil-feeding hollow motor shaft according to claim 1, characterized in that: The grooves are symmetrically radial, with an expansion angle of 3° on each side.

6. The spiral oil-feeding hollow motor shaft according to claim 1, characterized in that: The motor shaft is provided with multiple sets of oil outlet holes in the axial direction, and the multiple sets of oil outlet holes are evenly distributed in the axial direction of the motor shaft at equal intervals and in the radial direction at equal angles.

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