An electric spindle and machine tool

Abstract

The application provides an electric spindle and a machine tool. The electric spindle comprises a rotor, a shaft core sleeved in the rotor, a first flow channel formed between the rotor and the shaft core, a first end and a second end of the first flow channel, a stator sleeved on the rotor, a gap between the stator and the rotor, the gap being communicated with the second end, a shaft sleeve sleeved on the stator, an end of the shaft sleeve being provided with a bearing seat, a first inlet and an outlet being arranged on the bearing seat, the first inlet being communicated with the first end, and the outlet being communicated with the gap. According to the application, the defect that the shaft core cannot be fully cooled due to the low cooling efficiency of the shaft core of the electric spindle in the prior art and the thermal elongation of the shaft core caused by the high temperature can be overcome, and the machining precision of the machine tool can be improved.

Description

Technical Field

[0001] This invention belongs to the field of machine tool technology, specifically relating to an electric spindle and a machine tool. Background Technology

[0002] With the rapid development and increasing sophistication of electric drive technology (variable frequency speed regulation technology, electric motor vector control technology, etc.), the mechanical structure of the main drive system of high-speed CNC machine tools has been greatly simplified, essentially eliminating belt drive and gear drive. The machine tool spindle is directly driven by an internal electric motor, thus shortening the length of the main drive chain to zero and achieving "zero transmission" for the machine tool. This transmission structure, where the spindle motor and the machine tool spindle are integrated, makes the spindle component relatively independent from the machine tool's transmission system and overall structure, and is also known as an "electric spindle."

[0003] Because electric spindles integrate the motor into the spindle unit and operate at high speeds, the motor stator and rotor generate a large amount of heat during operation, causing the electric spindle temperature to rise and deteriorating its thermal and dynamic characteristics, thus affecting its normal operation. Therefore, it is essential to take measures to control the electric spindle temperature and keep it within a constant range. While motor stator cooling technology is mature in the industry, motor rotor cooling remains a challenge. During operation, coolant is transported from the cooling channels of the motor stator housing into the spindle core to cool the rotor. The fixed stator housing makes it difficult to form a good flow channel seal with the high-speed rotating spindle core, making it challenging to effectively cool the motor rotor.

[0004] A related technology proposes a rotor cooling structure in which a rotor support is fixed between the rotor core and the motor shaft. Multiple through holes are formed along the axial direction of the rotor support. A sealed coolant chamber is formed between the front and rear ends of the stator and rotor core and the front and rear end covers, and coolant is installed in this sealed coolant chamber. During operation, the heat generated by the rotor core is transferred to the rotor support. The rotation of the rotor core causes the coolant to splash, flowing through the through holes on the rotor support and transferring the heat from the rotor support to the motor housing. The heat is then dissipated through a water-cooling mechanism inside the motor housing. This solution can cool the motor stator, rotor, and core. However, because the coolant chamber is a sealed structure, as the motor continues to run, the coolant within the sealed chamber cannot exchange heat, and the temperature rises accordingly, resulting in a decrease in cooling effectiveness over time.

[0005] Another related technology proposes an electric spindle for rotor core cooling, comprising a sleeve, stator, rotor, front bearing assembly, rear bearing assembly, front bearing lock nut, rear bearing lock nut, bearing cap, and bearing housing. The stator is installed inside the sleeve, which has a stator cooling channel. The rotor consists of a rotor spindle and a rotor core. The rotor spindle is supported and rotated by the front and rear bearing assemblies. A spiral cooling groove rotating around the rotor axis is provided on the outer circumference of the rotor spindle. The rotor core is fitted around the rotor spindle, sealing the spiral cooling groove to form a rotor cooling channel. An air inlet channel communicating with the rotor cooling channel is provided on the front side wall of the sleeve, and an air outlet channel communicating with the rotor cooling channel is provided on the rear side wall of the sleeve and the bearing housing. In this design, the stator cooling channel communicates with the rotor cooling channel, but the high-speed rotating rotor cannot maintain constant communication with the fixed stator cooling channel. Only a small amount of cooling gas can enter the rotor cooling channel, resulting in low cooling efficiency.

[0006] Because existing electric spindles have low cooling efficiency for the spindle core, they cannot adequately cool the spindle core, leading to technical problems such as thermal expansion of the spindle core due to excessive temperature. Therefore, this invention studies and designs an electric spindle and machine tool. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the defect of low cooling efficiency of the spindle core in the prior art, which results in insufficient cooling of the spindle core and thermal expansion of the spindle core due to excessive temperature, thereby providing an electric spindle and machine tool.

[0008] To address the aforementioned problems, the present invention provides an electric spindle, comprising a rotor, a core sleeved inside the rotor, a first flow channel formed between the rotor and the core, the first flow channel having a first end and a second end, a stator sleeved on the rotor, a gap between the stator and the rotor, the gap communicating with the second end, a bushing sleeved on the stator, a bearing seat provided at the end of the bushing sleeve, a first inlet and an outlet provided on the bearing seat, the first inlet communicating with the first end, and the outlet communicating with the gap.

[0009] In some embodiments, the bearing housing includes a first part and a second part, the second part being sleeved on the shaft core, the first inlet and the outlet being disposed on the second part, the second part being disposed at the end of the shaft sleeve, the first part being disposed on the second part, and the first part being located between the second part and the stator, the first part having a second flow channel between the first part and the shaft core, one end of the second flow channel being connected to the gap, and the other end being connected to the outlet.

[0010] In some embodiments, the second part has a first groove on the side facing the first part, an oil baffle ring is provided in the first groove, a third flow channel is formed between the oil baffle ring and the inner wall of the first part and the first groove, the third flow channel is connected to the second flow channel, a second groove is provided on the bottom surface of the first groove, the second groove has a third end and a fourth end, the third end is connected to the third flow channel, and the fourth end is connected to the outlet.

[0011] In some embodiments, a first cavity is formed between the first portion, the stator, the rotor, and the shaft core, and the first cavity is connected to the second flow channel, the gap, and the first inlet.

[0012] In some embodiments, the shaft core is provided with a drainage hole and a third groove, one end of the drainage hole is connected to the first cavity, and the other end is connected to the third groove, which is connected to the first flow channel.

[0013] In some embodiments, the drainage hole is arranged circumferentially along the shaft core, the diameter of the drainage hole is D, the radius of the shaft core is R, and the distance between the inner wall of the drainage hole and the outer wall of the shaft core is H, which satisfies H = 0.15R + D.

[0014] In some embodiments, the first flow channel is arranged in a spiral shape, with a first end of the first flow channel located close to the bearing housing and a second end of the first flow channel located away from the bearing housing.

[0015] In some embodiments, the bushing is provided with a second inlet, which communicates with the first inlet, and the second inlet is located at the end of the bushing away from the bearing housing.

[0016] In some embodiments, a second cavity is formed between the stator end away from the bearing housing, the rotor end away from the bearing housing, and the bushing, and the second end and the gap are connected through the second cavity.

[0017] The present invention also provides a machine tool including the electric spindle described above.

[0018] The electric spindle and machine tool provided by this invention have the following beneficial effects:

[0019] Through the first inlet and outlet, when the coolant flows in through the first inlet, it cools the bearing housing. The cooled coolant then flows into the first flow channel, thereby cooling the inner walls of the shaft and rotor. Then, the coolant in the first flow channel flows into the gap between the stator and the rotor through the second end, thereby cooling the outer walls of the stator and the rotor. Both the inner and outer walls of the rotor are cooled, improving the cooling efficiency of the motor stator, rotor, and shaft, achieving synchronous cooling of the stator, rotor, and shaft, effectively reducing the temperature rise of the shaft, thus solving the problem of thermal expansion of the shaft due to excessive temperature, and thereby improving the machining accuracy of the machine tool. Attached Figure Description

[0020] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0021] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0022] Figure 1 This is an assembly diagram of the electric spindle according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the spindle core in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the first part of the electric spindle in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of the second part of the electric spindle in an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the oil baffle ring in the electric spindle according to an embodiment of the present invention;

[0027] Figure 6 for Figure 1 A magnified view of a portion of the image;

[0028] Figure 7 This is a schematic diagram of the structure of the first flow channel in the electric spindle according to an embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of the radial cross-section of the spindle core in an embodiment of the present invention.

[0030] The reference numerals in the attached figures are as follows:

[0031] 1. Bushing; 2. Stator; 3. Rotor; 4. Shaft core; 5. First part; 6. Second part; 7. Oil retaining ring; 8. First cavity; 9. Third groove; 10. Second inlet; 11. First flow channel; 12. First inlet; 13. Second groove; 14. Drain hole; 15. Outlet; 16. Bearing. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0035] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0036] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0037] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0038] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0039] See also Figures 1 to 7As shown, according to an embodiment of the present invention, an electric spindle is provided, including a rotor 3, a core 4 is sleeved inside the rotor 3, a first flow channel 11 is formed between the rotor 3 and the core 4, the first flow channel 11 has a first end and a second end, a stator 2 is sleeved on the rotor 3, a gap is formed between the stator 2 and the rotor 3, the gap is connected to the second end, a bushing 1 is sleeved on the stator 2, a bearing seat is provided at the end of the bushing 1, a first inlet 12 and an outlet 15 are provided on the bearing seat, the first inlet 12 is connected to the first end, and the outlet 15 is connected to the gap. In this technical solution, preferably, an outlet 15 is provided on the outer peripheral wall of the bearing housing. When coolant flows in through the first inlet 12 and the outlet 15, it cools the bearing housing. The cooled coolant then flows into the first flow channel 11, thereby cooling the inner walls of the shaft core 4 and the rotor 3. Then, the coolant in the first flow channel 11 flows into the gap between the stator 2 and the rotor 3 through the second end, thereby cooling the outer walls of the stator 2 and the rotor 3. This application improves the cooling efficiency of the motor stator 2, the rotor 3 and the shaft core 4 by cooling both the inner and outer walls of the rotor 3, achieving synchronous cooling of the stator 2, the rotor 3 and the shaft core 4, effectively reducing the temperature rise of the shaft core 4, thus solving the problem of thermal expansion of the shaft core 4 due to excessive temperature, and improving the machining accuracy of the machine tool.

[0040] In some embodiments, the bearing housing includes a first part 5 and a second part 6. The second part 6 is sleeved on the shaft core 4. A first inlet 12 and an outlet 15 are disposed on the second part 6, which is located at the end of the bushing 1. The first part 5 is disposed on the second part 6 and is located between the second part 6 and the stator 2. A second flow channel is formed between the first part 5 and the shaft core 4. One end of the second flow channel is connected to a gap, and the other end is connected to the outlet 15. In this technical solution, the outlet 15 is disposed on the outer peripheral wall of the second part 6, and a bearing 16 is disposed between the second part 6 and the shaft core 4. The first part 5 and the second part 6 adopt a separate structure, but an integral structure can also be adopted. Both the first part 5 and the second part 6 are annular, and the first part 5 is also sleeved on the shaft core 4. Coolant flows in through the first inlet 12 and then into the first flow channel 11, thereby cooling the inner walls of the shaft core 4 and the rotor 3. The coolant in the first flow channel 11 flows into the gap between the stator 2 and the rotor 3 through the second end, thereby cooling the outer walls of the stator 2 and the rotor 3, thus achieving cooling of both the inner and outer walls of the rotor 3. The coolant flowing out from the gap between the stator 2 and the rotor 3 is discharged from the outlet 15 through the second flow channel.

[0041] In some implementations, see reference Figures 3 to 5As shown, a first groove is provided on the side of the second part 6 facing the first part 5. An oil-blocking ring 7 is provided in the first groove, and a third flow channel is formed between the oil-blocking ring 7, the first part 5, and the inner wall of the first groove. The third flow channel is connected to the second flow channel. A second groove 13 is provided on the bottom surface of the first groove. The second groove 13 has a third end and a fourth end. The third end is connected to the third flow channel, and the fourth end is connected to the outlet 15. In this technical solution, the first groove and the second groove are annular. The oil-blocking ring 7 is sleeved on the shaft core 4 to seal the shaft core 4 and the second part 6, so that the coolant in the second flow channel can only flow into the third flow channel. Through the second flow channel, the third flow channel, and the second groove, the flow path of the coolant in the bearing housing is increased, thereby improving the cooling effect of the bearing housing. The bearing housing can be a split structure, consisting of the first part 5 and the second part 6, which are fixed together by screws. The split bearing housing is equipped with a first inlet 12, an outlet 15, and a second groove 13, which can realize heat exchange between the electric spindle and the outside. The combination structure of the split bearing housing and the oil retainer ring 7 solves the problems of oil retainer ring not being able to be assembled and poor bearing housing sealing.

[0042] The oil baffle ring 7 is fixed to the shaft core 4 by an interference fit and is assembled between the first part 5 and the second part 6. This allows the coolant in the third groove 9 to be introduced into the annular second groove 13 of the second part 6 and discharged through the outlet 15, effectively improving the sealing effect of the bearing chamber.

[0043] In some embodiments, a first cavity 8 is formed by the first part 5, the stator 2, the rotor 3, and the shaft core 4, and the first cavity 8 is connected to the second flow channel, the gap, and the first inlet 12. In this technical solution, see [reference needed]. Figure 1 As shown, the first inlet 12 is arranged axially along the bearing housing. An inflow channel is provided radially on the bearing housing, and the inflow channel is connected to the first inlet 12. Coolant flows into the first cavity 8 through the first inlet 12. The first cavity 8 can store coolant to ensure the cooling effect of the electric spindle. When the coolant in the first cavity 8 flows into the first flow channel 11, it cools the inner walls of the shaft core 4 and rotor 3. Then, the coolant in the first flow channel 11 flows into the gap between the stator 2 and rotor 3 through the second end, thereby cooling the outer walls of the stator 2 and rotor 3. The coolant in the gap flows back into the first cavity 8, thus forming a circulation loop. The first cavity 8 is also connected to the second flow channel, so that part of the coolant in the first cavity 8 is discharged from the outlet 15 through the second flow channel, and coolant continuously flows into the first inlet 12, thereby ensuring the amount of coolant in the first cavity 8.

[0044] In some implementations, see reference Figure 2As shown, the shaft core 4 is provided with a drainage hole 14 and a third groove 9. One end of the drainage hole 14 is connected to the first cavity 8, and the other end is connected to the third groove 9. The third groove 9 is connected to the first flow channel 11. In this technical solution, when the shaft core 4 rotates, under the action of centrifugal force, the coolant in the first cavity 8 flows into the third groove 9 through the drainage hole 14, thereby providing coolant to the first flow channel to cool the shaft core 4.

[0045] The electric spindle of this invention employs a circulating cooling channel in the spindle core 4. The spindle core 4 has multiple right-handed drain holes 14, a third groove 9, and a semi-enclosed first channel structure, which allows for the continuous flow of coolant. A first cavity 8 is provided inside the electric spindle, communicating with the outside of the spindle to ensure that the cooling system maintains heat exchange with the outside environment, thereby improving the cooling efficiency of the motor stator, rotor, and spindle core. This solves the problem of low cooling efficiency caused by the inability of existing coolant to exchange heat with the outside environment in the closed cooling cavity of the rotor.

[0046] The drain hole 14 is clockwise, matching the first flow channel. The distance between the inner wall of the drain hole 14 and the outer wall of the shaft core 4 is H, where H = 0.15R + D, R is the radius of the shaft core 4, ranging from [60, 150], and D is the diameter of the drain hole 14, ranging from [2, 4]. The angle α between the drain hole 14 and the axis of the shaft core 4 is between 58° and 72°. The drain hole 14 connects the first cavity 8 and the third groove 9. When the shaft core 4 is working, the shaft core 4 drives the coolant to rotate. The coolant is subjected to centrifugal force and flows upward from the drain hole 14 into the first flow channel 11, and flows out from the second end of the upper first flow channel 11.

[0047] The lower end of the first flow channel 11 is located in the middle of the third groove 9 and 1.5-2.5mm away from the bottom of the third groove 9. It can drive the coolant to rotate and enter the spiral first flow channel 11 through centrifugal force to flow upward, thereby cooling the shaft core 4 and the rotor 3.

[0048] The second end of the spiral first flow channel 11 is 3-6mm higher than the top of the rotor 3, forming a semi-open spiral water tank, which causes the coolant in the spiral water tank to splash outward and flow into the gap between the stator 2 and the rotor 3 to cool the stator and rotor.

[0049] In some embodiments, the drainage hole 14 is arranged circumferentially along the shaft core 4. The diameter of the drainage hole 14 is D, the radius of the shaft core 4 is R, and the distance between the inner wall of the drainage hole 14 and the outer wall of the shaft core 4 is H, which satisfies H = 0.15R + D. In this technical solution, the direction of the drainage hole 14 is right-handed, matching the first flow channel. Of course, other forms are also possible, as long as the coolant in the first cavity 8 can be introduced into the first flow channel. The drainage hole 14 is located at a distance of H from the shaft core wall thickness, where H = 0.15R + D, R is the radius of the shaft core 4, with a value range of [60, 150], and D is the diameter of the drainage hole, with a value range of [2, 4]. The angle α between the drainage hole 14 and the axis of the shaft core 4 is between 58° and 72°. It connects the first cavity 8 and the third groove 9. When the shaft core 4 is working, the shaft core 4 drives the coolant to rotate. The coolant is subjected to centrifugal force and flows upward from the drainage hole 14 into the third groove 9, and then into the first flow channel.

[0050] In some implementations, see reference Figure 7 As shown, the first flow channel 11 is arranged in a spiral shape, with its first end close to the bearing housing and its second end away from the bearing housing. In this technical solution, a groove is provided on the surface of the shaft core 4, arranged in a spiral shape. This ensures that when the shaft core 4 is fitted into the rotor 3, the first flow channel 11 is spirally arranged, increasing the flow length of the first flow channel 11 and improving the cooling area and cooling effect of the rotor 3 and shaft core 4. The inlet of the first flow channel 11 is close to the bearing housing, and the outlet of the first flow channel 11 is away from the bearing housing. When the electric spindle is used vertically, a height difference exists between the inlet and outlet of the first flow channel 11, increasing the cooling time of the cooling water in the first flow channel 11, improving cooling efficiency, and achieving efficient utilization of the cooling water.

[0051] In some embodiments, the bushing 1 is provided with a second inlet 10, which communicates with the first inlet 12, and the second inlet 10 is located at the end of the bushing 1 away from the bearing seat. In this technical solution, see [reference needed]. Figure 6 As shown, the second inlet 10 is located at the end of the bushing 1 away from the bearing housing, that is, the second inlet 10 is arranged along the axial direction of the bushing 1. This arrangement allows the coolant flowing into the bushing 1 from the second inlet 10 to also cool the bushing 1, further improving the cooling effect of the electric spindle. To connect the second inlet 10 with the first inlet 12, a connecting hole is provided radially in the bearing housing, thereby connecting the second inlet 10 with the first inlet 12. Figure 6As shown, the opening of the connecting hole is located on the outer peripheral wall of the bearing housing to facilitate the machining of the connecting hole. In use, the opening of the connecting hole on the outer peripheral wall of the bearing housing is simply sealed. The first inlet 12 is always in an oil supply state, ensuring that the coolant in the first cavity 8 is maintained at a certain level. Part of the oil in the first cavity 8 enters the upper first flow channel through the drainage hole 14. Another part of the oil flows to the outlet 15 through the third flow channel, and the oil output is controlled by the flow rate of the third flow channel. This ensures that coolant and cold oil flow out, achieving alternating hot and cold coolant flow. Of course, in this invention, to ensure the amount of liquid stored in the first cavity 8, preferably, the flow rates of the second inlet 10 and the first inlet 12 are greater than the flow rate of the outlet 15. The first flow channel 11 is connected to the second inlet 10, enabling synchronous cooling of the bushing 1 and stator 2. This effectively reduces the temperature rise of the spindle motor, thereby reducing the thermal expansion of the spindle core 4 due to excessive temperature, and ultimately improving the machining accuracy of the machine tool. It also solves the problem of motor heat being transferred to the front bearing through the spindle, leading to excessively high front bearing temperature and reduced bearing life. Furthermore, it addresses the issue in existing technologies where insufficient cooling of the motor rotor and spindle core causes thermal expansion of the spindle core, affecting the machining accuracy of the electric spindle.

[0052] In some embodiments, a second cavity is formed between the stator 2 at the end away from the bearing housing, the rotor at the end away from the bearing housing, and the bushing 1, and the second end and the gap are connected through the second cavity. In this technical solution, the electric spindle of the present invention includes a spindle core 4, a first cavity 8, a first flow channel 11, and a drainage hole 14 disposed on the spindle core, and a split front bearing housing including a first part 5 and a second part 6, a first inlet 12, a second groove 13, and an outlet 15 disposed in the second part 6, and an oil retaining ring 7 for the first part 5.

[0053] The sleeve 1 of the electric spindle mates with the second part 6. The second inlet 10 on the sleeve 1 communicates with the first inlet 12 of the second part 6, forming the liquid inlet section of the cooling circulation system. The spindle core 4 is interference-fitted with the rotor 3. The spindle core 4 has a spirally arranged groove structure, which forms a first flow channel 11 with the electric rotor 3. The oil baffle ring 7 is interference-fitted with the spindle core 4. The oil baffle ring 7 is installed above the annular second groove 13 of the second part 6. Preferably, the oil baffle ring 7 is installed 1 mm above the annular second groove 13 of the second part 6. There is a certain gap between the oil baffle ring 7 and the inner hole of the first part 5, so that the coolant flows from the gap to the second groove 13 and into the outlet 15, forming the oil return system.

[0054] Coolant enters through the second inlet 15, flows into the first inlet 12 connecting the second part 6 and the first part 5, and is stored in the first cavity 8 inside the electric spindle. In actual use, the coolant level is 10mm below the bottom of the rotor 3. The lower end of the drainage hole 14 on the spindle core 4 is immersed in the coolant in the first cavity 8, and the upper end connects to the third groove 9. Preferably, the drainage hole 14 is at a 30° angle. When the electric spindle is working, the drainage hole 14 rotates with the spindle core 1, and the centrifugal force drives the coolant into the third groove 9. The lower end of the spirally arranged groove on the spindle core 1 is located in the middle of the third groove 9. The coolant rises with the spiral groove 11 under the action of centrifugal force, splashes outward from the unclosed spiral groove opening at the upper end, and flows down back into the first cavity 8 along the gap between the stator 2 and the rotor 3. The coolant in the first cavity 8 flows into the annular second groove 13 along the third flow channel between the oil baffle ring 7 and the first part 5. The coolant gathers in the annular second groove 13 and flows out to the outside of the electric spindle, forming a complete cooling system. This system achieves synchronous cooling of the spindle core 4, rotor 3 and stator 2, heat exchange of the coolant and sealing of the bearing chamber, improves the cooling efficiency of the spindle core 4, motor rotor 3 and motor stator 2, effectively reduces the temperature rise of the spindle motor, thereby reducing the thermal expansion problem of the spindle core due to excessive temperature, and thus improving the machining accuracy of the machine tool.

[0055] The present invention also provides a machine tool including the above-described electric spindle.

[0056] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. An electric spindle, characterized in that, The device includes a rotor (3), a shaft core (4) is sleeved inside the rotor (3), a first flow channel (11) is formed between the rotor (3) and the shaft core (4), the first flow channel (11) has a first end and a second end, a stator (2) is sleeved on the rotor (3), there is a gap between the stator (2) and the rotor (3), the gap is connected to the second end, a bushing (1) is sleeved on the stator (2), a bearing seat is provided at the end of the bushing (1), a first inlet (12) and an outlet (15) are provided on the bearing seat, the first inlet (12) is connected to the first end, and the outlet (15) is connected to the gap.

2. The electric spindle according to claim 1, characterized in that, The bearing housing includes a first part (5) and a second part (6). The second part (6) is sleeved on the shaft core (4). The first inlet (12) and the outlet (15) are disposed on the second part (6). The second part (6) is disposed at the end of the bushing (1). The first part (5) is disposed on the second part (6). The first part (5) is located between the second part (6) and the stator (2). A second flow channel is provided between the first part (5) and the shaft core (4). One end of the second flow channel is connected to the gap, and the other end is connected to the outlet (15).

3. The electric spindle according to claim 2, characterized in that, The second part (6) is provided with a first groove on the side facing the first part (5). An oil baffle ring (7) is provided in the first groove. A third flow channel is formed between the oil baffle ring (7) and the inner wall of the first part (5) and the first groove. The third flow channel is connected to the second flow channel. A second groove (13) is provided on the bottom surface of the first groove. The second groove (13) has a third end and a fourth end. The third end is connected to the third flow channel, and the fourth end is connected to the outlet (15).

4. The electric spindle according to claim 2, characterized in that, The first cavity (8) is formed by the first part (5), the stator (2), the rotor (3) and the shaft core (4), and the first cavity (8) is connected to the second flow channel, the gap and the first inlet (12).

5. The electric spindle according to claim 4, characterized in that, The shaft core (4) is provided with a flow hole (14) and a third groove (9). One end of the flow hole (14) is connected to the first cavity (8), and the other end is connected to the third groove (9). The third groove (9) is connected to the first flow channel (11).

6. The electric spindle according to claim 5, characterized in that, The drainage hole (14) is arranged circumferentially along the shaft core (4). The diameter of the drainage hole (14) is D, the radius of the shaft core (4) is R, and the distance between the inner wall of the drainage hole (14) and the outer wall of the shaft core (4) is H, which satisfies H=0.15R+D.

7. The electric spindle according to claim 1, characterized in that, The first flow channel (11) is arranged in a spiral shape, and the first end of the first flow channel (11) is located close to the bearing seat, while the second end of the first flow channel (11) is located away from the bearing seat.

8. The electric spindle according to claim 1, characterized in that, The bushing (1) is provided with a second inlet (10), which is connected to the first inlet (12). The second inlet (10) is located at the end of the bushing (1) away from the bearing seat.

9. The electric spindle according to claim 1, characterized in that, A second cavity is formed between the end of the stator (2) away from the bearing seat, the end of the rotor away from the bearing seat, and the bushing (1), and the second end and the gap are connected through the second cavity.

10. A machine tool, characterized in that, Includes an electric spindle as described in any one of claims 1 to 9.

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