Rotor shaft and motor assembly

Abstract

The invention provides a rotor shaft and a motor assembly, the interior of the rotor shaft is a hollow cavity, an output shaft (FO) of a motor coaxially penetrates through the rotor shaft from the hollow cavity, the hollow cavity comprises a liquid inlet section (10), a liquid storage section (20) and a liquid outlet section (30), the liquid storage section (20) is located in the middle area in the axial direction of a rotor (R), and the liquid outlet section (30) is located in the middle area in the axial direction of the rotor (R). The rotor shaft further comprises a first end liquid outlet hole (60) and a second end liquid outlet hole (70) which are communicated with the hollow cavity and the external space of the rotor shaft, cooling liquid can flow into the hollow cavity from the liquid inlet section (10), then partially flow out of the first end liquid outlet hole (60), partially flow to the liquid storage section (20) and the liquid outlet section (30) and finally flow out of the second end liquid outlet hole (70). According to the rotor shaft, the cooling liquid can be guided to be distributed to the cooling areas at reasonable flow, and good cooling is provided for a motor assembly with coaxial input and output shafts. The motor assembly is simple and compact in structure and good in cooling effect.

Description

Technical Field

[0001] The present invention relates to the field of motors, and more particularly to a rotor shaft and a motor assembly. Background Art

[0002] Taking the motor of new energy vehicles as an example, the motor will generate a lot of heat during high-speed rotation. If the motor is not cooled in time, the motor efficiency will decrease or even malfunction.

[0003] For a rotor with coaxial input and output shafts, how to effectively guide the cooling oil to flow near the rotor and reasonably distribute the coolant so that the rotor can be effectively cooled is a problem that needs to be solved urgently in this field. Summary of the invention

[0004] The purpose of the present invention is to overcome or at least alleviate the deficiencies of the above-mentioned prior art and to provide a rotor shaft and motor assembly with good cooling effect.

[0005] According to a first aspect of the present invention, there is provided a rotor shaft for being non-rotatably connected to a rotor of a motor. The interior of the rotor shaft is a hollow cavity, and the output shaft of the motor can coaxially pass through the rotor shaft from the hollow cavity. The hollow cavity includes a liquid inlet section, a liquid storage section and a liquid outlet section, and the inner diameters of the liquid inlet section, the liquid storage section and the liquid outlet section are all larger than the outer diameter of the output shaft. When the rotor shaft is assembled with the rotor, the liquid storage section is located in the middle area of ​​the rotor in the axial direction. The rotor shaft further comprises a first end liquid outlet hole and a second end liquid outlet hole communicating with the hollow cavity and the external space of the rotor shaft. The cooling liquid can flow into the hollow cavity from the liquid inlet section, then partially flow out from the first end liquid outlet, partially flow to the liquid storage section and the liquid outlet section, and finally flow out from the second end liquid outlet.

[0006] In at least one embodiment, the inner diameter of the liquid inlet section is smaller than the inner diameter of the liquid storage section. The hollow cavity further comprises a first diameter-changing section, and the first diameter-changing section connects the liquid inlet section and the liquid storage section.

[0007] In at least one embodiment, the opening of the first end liquid outlet hole located in the hollow cavity is arranged in the first diameter-changing section.

[0008] In at least one embodiment, the axial position of the first end liquid outlet on the first diameter-changing section satisfies: 15% to 25% of the coolant flowing through the first diameter-changing section flows out from the first end liquid outlet, and the remaining 85% to 75% flows into the liquid storage section.

[0009] In at least one embodiment, the inner diameter of the liquid outlet section is smaller than the inner diameter of the liquid storage section.

[0010] In at least one embodiment, the opening of the second end liquid outlet hole located in the hollow cavity is arranged in the liquid outlet section.

[0011] In at least one embodiment, the inner diameter of the liquid outlet section is greater than the inner diameter of the liquid inlet section.

[0012] In at least one embodiment, the first end liquid outlet hole comprises a first end liquid outlet hole small section and a first end liquid outlet hole large section, and in the radial direction of the rotor shaft, the first end liquid outlet hole small section is closer to the hollow cavity than the first end liquid outlet hole large section, and / or The second end liquid outlet hole comprises a second end liquid outlet hole small section and a second end liquid outlet hole large section. In the radial direction of the rotor shaft, the second end liquid outlet hole small section is closer to the hollow cavity than the second end liquid outlet hole large section.

[0013] According to a second aspect of the present application, a motor assembly is provided, comprising a stator, a rotor, a rotor shaft and an output shaft, wherein the rotor is arranged on the inner circumference of the stator, the rotor shaft is connected to the rotor in a non-rotatable manner, and the output shaft can pass through the inside of the rotor shaft in a rotatable manner relative to the rotor shaft, wherein: The rotor shaft is the rotor shaft according to the first aspect of the present application.

[0014] In at least one embodiment, in the axial direction of the rotor, the liquid storage section of the rotor shaft covers more than 90% of the axial area of ​​the rotor, and the coolant flowing out of the first end liquid outlet hole and the second end liquid outlet hole of the rotor shaft can be sprayed to the two axial ends of the rotor.

[0015] The rotor shaft according to the present application can guide the coolant to be distributed to each cooling area with a reasonable flow rate, providing good cooling for the motor assembly with the input and output shafts coaxial. The motor assembly according to the present application has a simple and compact structure and good cooling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the main components of a motor assembly according to an embodiment of the present application.

[0017] Figure 2 yes Figure 1 Schematic diagram of an axial section.

[0018] Figure 3 yes Figure 1 sectional view of .

[0019] Figure 4It is a schematic structural diagram of a rotor shaft according to an embodiment of the present application.

[0020] Figure 5 yes Figure 4 Schematic diagram of an axial section.

[0021] Description of reference numerals: S stator; R rotor; FO output shaft; C1 first end cover; C2 second end cover; C20 liquid inlet channel; FR rotor shaft; 10 liquid inlet section; 20 liquid storage section; 30 liquid outlet section; 40 first diameter reducing section; 50 second diameter reducing section; 60 first end liquid outlet hole; 61 first end liquid outlet hole small section; 62 first end liquid outlet hole large section; 70 second end liquid outlet hole; 71 second end liquid outlet hole small section; 72 second end liquid outlet hole large section; 80 closed section; s1 first sealing device; s2 second sealing device. DETAILED DESCRIPTION

[0022] The exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present invention, and are not intended to exhaust all possible modes of the present invention, nor to limit the scope of the present invention.

[0023] Reference Figures 1 to 5 , introduces a motor assembly and a rotor shaft FR thereof according to an embodiment of the present application. Unless otherwise specified, the radial, axial and circumferential directions referred to below are all based on the radial, axial and circumferential directions of the rotor shaft FR.

[0024] The motor assembly of this embodiment includes a stator S, a rotor R, a rotor shaft FR, an output shaft FO and a housing. The rotor R is arranged on the inner periphery of the stator S, and the rotor shaft FR passes through the rotor R and is connected to the rotor R in a non-rotatable manner. The rotor shaft FR is a hollow shaft, and the output shaft FO passes through the rotor shaft FR, is coaxial with the rotor shaft FR, and the two are connected in a relatively rotatable manner, and the two are connected via a transmission, which is not shown in the figure.

[0025] In order to conveniently show the internal structure of the motor assembly, only the end cover part of the housing is shown in the figure, including the first end cover C1 and the second end cover C2. The first end cover C1 is arranged at one axial end of the stator S and the rotor R, and the first end cover C1 provides support for the rotor shaft FR through the first bearing B1. The second end cover C2 is arranged on the axial side of the first end cover C1 away from the stator and the rotor, and the second end cover C2 provides support for the output shaft FO through the second bearing B2. The second end cover C2 is provided with a liquid inlet channel C20 for introducing coolant (such as oil from the gearbox) into the interior of the motor.

[0026] Next, the coolant flow channel inside the motor is introduced in detail. The main structure of the coolant flow channel relies on the rotor shaft FR.

[0027] The hollow cavity inside the rotor shaft FR can be divided into 6 sections according to the different inner diameter sizes. Along the flow direction of the coolant in the axial direction of the rotor shaft FR, the 6 sections are: the liquid inlet section 10, the first diameter-changing section 40, the liquid storage section 20, the second diameter-changing section 50, the liquid outlet section 30 and the closed section 80. The inner diameters of the liquid inlet section 10, the liquid storage section 20, the liquid outlet section 30 and the closed section 80 in different axial regions are equal. They are arranged in order from large to small in terms of inner diameter, and are: the liquid storage section 20, the liquid outlet section 30, the liquid inlet section 10 and the closed section 80, and their inner diameters are all larger than the outer diameter of the output shaft FO. Among them, the inner diameter of the closed section 80 is slightly larger than the outer diameter of the output shaft FO to a degree very close to the outer diameter of the output shaft FO, so that the rotor shaft FR and the output shaft FO do not contact, but the coolant basically does not flow through the closed section 80. It can be understood that since the closed section 80 is ultimately open to the gearbox, even a small amount of coolant flowing out through the closed section 80 is permitted; in addition, in certain possible cases, coolant flowing from the gearbox into the rotor shaft FR through the closed section 80 is permitted.

[0028] The first reducing section 40 connects the liquid inlet section 10 and the liquid storage section 20, and the inner diameter of the first reducing section 40 gradually increases along the axial direction from the side where the liquid inlet section 10 is located to the side where the liquid storage section 20 is located; the second reducing section 50 connects the liquid outlet section 30 and the liquid storage section 20, and the inner diameter of the second reducing section 50 gradually decreases along the axial direction from the side where the liquid storage section 20 is located to the side where the liquid outlet section 30 is located.

[0029] One end of the liquid inlet section 10 is connected to the liquid inlet channel C20, so that the coolant can be conducted to the hollow cavity inside the rotor shaft FR through the liquid inlet channel C20. An annular first sealing device s1 and a second sealing device s2 are arranged in the axial direction of the connection area between the liquid inlet section 10 and the liquid inlet channel C20. The first sealing device s1 is arranged between the second end cover C2 and the output shaft FO, and the second sealing device s2 is arranged between the second end cover C2 and the rotor shaft FR.

[0030] Since the liquid storage section 20 is the section with the largest inner diameter in the hollow cavity, it also means that the hydraulic pressure of this section is relatively the smallest, which makes it easy for the coolant to accumulate in the liquid storage section 20. It should be understood that during the operation of the motor, the coolant is flowing and circulating, so the "accumulation" mentioned here is a dynamic process, which does not mean that the coolant in the liquid storage section 20 remains stationary, but the coolant in the liquid storage section 20 is constantly flowing toward the liquid outlet section 30; "accumulation" means that at any moment in the operation of the motor, the liquid storage section 20 is roughly filled or nearly filled with coolant, rather than only a small amount of coolant attached to the area such as the inner circumferential wall close to the rotor shaft FR (because the coolant rotates with the rotor shaft FR and is subjected to centrifugal force, it is possible that the coolant in the liquid storage section 20 is scarce when the hollow cavity structure is not designed properly). The coolant in the liquid storage section 20 can be dynamically accumulated in large quantities, so that the heat exchange capacity of the liquid storage section 20 is strong. In this embodiment, the liquid storage section 20 is located in the axial center of the rotor R, and the liquid storage section 20 covers more than 90% of the axial area of ​​the rotor R, so that the main body of the rotor R can exchange heat with the coolant in the liquid storage section 20 through heat conduction, and the heat dissipation effect of the rotor R is good.

[0031] Since the inner diameter of the liquid outlet section 30 is larger than that of the liquid inlet section 10 , the hydraulic pressure in the liquid outlet section 30 is relatively smaller than that in the liquid inlet section 10 , making it easier for the coolant to flow from the liquid inlet section 10 to the liquid outlet section 30 .

[0032] The rotor shaft FR forms a plurality of (four in this embodiment) second end liquid outlet holes 70 on the peripheral wall of the axial region where the liquid outlet section 30 is located, and the second end liquid outlet holes 70 are connected in the radial direction of the rotor shaft FR. The second end liquid outlet holes 70 are located in the region close to the axial end of the rotor R in the axial direction. Since the closed section 80 hardly allows the coolant to pass through, the coolant flowing to the liquid outlet section 30 will eventually be ejected from the second end liquid outlet hole 70 to the end of the rotor R, thereby cooling the end of the rotor R in a direct contact manner; in addition, this part of the coolant can also be ejected to the end of the stator S along the ejection path, thereby achieving the purpose of cooling the stator S.

[0033] The minimum inner diameter of the second end liquid outlet hole 70 is very small, for example, 2 mm, so as to form an outflowing water flow with a certain impact force. For the convenience of drilling process, the second end liquid outlet hole 70 is divided into two sections, a second end liquid outlet hole small section 71 and a second end liquid outlet hole large section 72, and the second end liquid outlet hole large section 72 is closer to the outer periphery of the rotor shaft FR. Therefore, when drilling, the second end liquid outlet hole large section 72 can be first drilled from the outer periphery of the rotor shaft FR (easier to achieve), and then the second end liquid outlet hole small section 71 can be drilled from the remaining thinner peripheral wall on the inner side.

[0034] The rotor shaft FR has a plurality of (four in this embodiment) first end liquid outlet holes 60 formed on the peripheral wall of the axial region where the first diameter reducing section 40 is located. The first end liquid outlet holes 60 are connected in the radial direction of the rotor shaft FR. The first end liquid outlet holes 60 are located in the region of the rotor R close to the other axial end in the axial direction.

[0035] When the coolant flows from the liquid inlet section 10 to the liquid storage section 20, a small portion of the coolant will be ejected from the first end liquid outlet 60 to the end of the rotor R, thereby directly contacting the end of the rotor R to cool it. Similarly, this portion of the coolant can also be ejected to the end of the stator S along the ejection path, thereby cooling the stator S.

[0036] Since the rotor shaft FR expands radially outward in a cone shape along the flow direction of the coolant, the coolant flows along the inner wall of the first variable diameter section 40 under the action of centrifugal force and tends to flow radially outward. This tendency brought about by the centrifugal force can cause part of the coolant to flow through the first end liquid outlet 60 instead of all of it flowing to the liquid storage section 20.

[0037] It should be understood that the coolant flowing out of the first end outlet hole 60 accounts for only a small part of the flowing coolant. Preferably, for example, 15% to 25% of the coolant flowing through the first diameter-reducing section 40 flows out of the first end outlet hole 60, and the remaining 85% to 75% further flows into the liquid storage section 20. The specific proportion of the coolant flowing out of the first end outlet hole 60 can be adaptively designed according to the requirements of the motor design. By changing the position of the first end outlet hole 60 in the first diameter-reducing section 40, and / or changing the opening size of the first end outlet hole 60, and / or changing the number of the first end outlet holes 60, the proportion of the coolant flowing out of the first end outlet hole 60 can be changed.

[0038] The first end liquid outlet hole 60 is also divided into two sections, a first end liquid outlet hole small section 61 and a first end liquid outlet hole large section 62 . The first end liquid outlet hole large section 62 is closer to the outer periphery of the rotor shaft FR.

[0039] In addition to facilitating the drilling process, the structure of the first end liquid outlet hole 60 being small inside and large outside (small inside near the hollow cavity and large outside near the outer space outside the shaft) is also conducive to controlling the amount of coolant flowing out, so that too much coolant is not ejected through the first end liquid outlet hole 60. It is worth noting that although the second end liquid outlet hole 70 introduced above has a similar structure, it is not used to limit the amount of coolant flowing out, because as the end of the flow channel, almost all the coolant flowing to the liquid outlet section 30 will be ejected from the second end liquid outlet hole 70.

[0040] Figure 3The thick arrows in the figure schematically show the flow path of the coolant in the motor assembly. In summary, the coolant flowing through the rotor shaft SR can provide the rotor with coolant in three areas: (1) cooling the axial first end of the rotor R and the stator S through the first end outlet hole 60, (2) cooling the axial second end of the rotor R and the stator S through the second end outlet hole 70, and (3) cooling the main part of the rotor R through dynamic accumulation in the liquid storage section 20.

[0041] It should be understood that the above-mentioned embodiments and some aspects or features thereof may be appropriately combined.

[0042] The present invention has at least one of the following advantages: (i) By properly arranging the cavity within the rotor shaft FR (including the segmentation of the cavity and the axial position of the cavity relative to the rotor R), the main body area of ​​the rotor of the motor assembly in which the input and output shafts are coaxially arranged, as well as the ends of the rotor and stator, can be well cooled.

[0043] (ii) By properly arranging the liquid inlet section 10, the first diameter-reducing section 40, the liquid storage section 20, the second diameter-reducing section 50 and the liquid outlet section 30, the coolant can flow smoothly along a preset direction instead of being statically accumulated in certain areas, thereby achieving a good cooling effect for the entire motor assembly.

[0044] Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art may make various modifications to the above-mentioned embodiments of the present invention under the guidance of the present invention without departing from the scope of the present invention.

Claims

1. A rotor shaft, used to be connected to a rotor (R) of a motor in a non-rotatable manner, characterized in that: The interior of the rotor shaft is a hollow cavity, and the output shaft (FO) of the motor can coaxially pass through the rotor shaft from the hollow cavity. The hollow cavity comprises a liquid inlet section (10), a liquid storage section (20) and a liquid outlet section (30); the inner diameters of the liquid inlet section (10), the liquid storage section (20) and the liquid outlet section (30) are all larger than the outer diameter of the output shaft (FO); When the rotor shaft and the rotor (R) are assembled, the liquid storage section (20) is located in the middle area of ​​the rotor (R) in the axial direction. The rotor shaft further comprises a first end liquid outlet hole (60) and a second end liquid outlet hole (70) communicating with the hollow cavity and the external space of the rotor shaft. The cooling liquid can flow into the hollow cavity from the liquid inlet section (10), then partially flow out from the first end liquid outlet hole (60), partially flow to the liquid storage section (20) and the liquid outlet section (30), and finally flow out from the second end liquid outlet hole (70).

2. The rotor shaft according to claim 1, characterized in that The inner diameter of the liquid inlet section (10) is smaller than the inner diameter of the liquid storage section (20). The hollow cavity further comprises a first diameter-changing section (40), wherein the first diameter-changing section (40) connects the liquid inlet section (10) and the liquid storage section (20).

3. The rotor shaft according to claim 2, characterized in that The opening of the first end liquid outlet hole (60) located in the hollow cavity is arranged in the first diameter-changing section (40).

4. The rotor shaft according to claim 2, characterized in that The axial position of the first end liquid outlet hole (60) on the first diameter-changing section (40) satisfies the condition that 15% to 25% of the cooling liquid flowing through the first diameter-changing section (40) flows out from the first end liquid outlet hole (60), and the remaining 85% to 75% flows into the liquid storage section (20).

5. The rotor shaft according to claim 1, characterized in that The inner diameter of the liquid outlet section (30) is smaller than the inner diameter of the liquid storage section (20).

6. The rotor shaft according to claim 1, characterized in that The opening of the second end liquid outlet hole (70) located in the hollow cavity is arranged in the liquid outlet section (30).

7. The rotor shaft according to claim 1, characterized in that The inner diameter of the liquid outlet section (30) is greater than the inner diameter of the liquid inlet section (10).

8. The rotor shaft according to claim 1, characterized in that The first end liquid outlet hole (60) comprises a first end liquid outlet hole small section (61) and a first end liquid outlet hole large section (62); in the radial direction of the rotor shaft, the first end liquid outlet hole small section (61) is closer to the hollow cavity than the first end liquid outlet hole large section (62); and / or The second end liquid outlet hole (70) comprises a second end liquid outlet hole small section (71) and a second end liquid outlet hole large section (72); in the radial direction of the rotor shaft, the second end liquid outlet hole small section (71) is closer to the hollow cavity than the second end liquid outlet hole large section (72).

9. A motor assembly, comprising a stator (S), a rotor (R), a rotor shaft (FR) and an output shaft (FO), wherein the rotor (R) is arranged on the inner circumference of the stator (S), the rotor shaft (FR) is connected to the rotor (R) in a non-rotatable manner, and the output shaft (FO) is rotatable relative to the rotor shaft (FR) and passes through the inside of the rotor shaft (FR), characterized in that: The rotor shaft (FR) is a rotor shaft according to any one of claims 1 to 8.

10. The motor assembly according to claim 9, characterized in that: In the axial direction of the rotor (R), the liquid storage section (20) of the rotor shaft (FR) covers more than 90% of the axial area of ​​the rotor (R), and the coolant flowing out of the first end liquid outlet hole (60) and the second end liquid outlet hole (70) of the rotor shaft (FR) can be sprayed to the two axial ends of the rotor (R).

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