Electric spindles and machine tools using them

Abstract

This invention provides an electric spindle and a machine tool using the same. The electric spindle includes a spindle core, a motor rotor assembly, a motor stator assembly, a first bearing housing, a first bearing, a second bearing housing, a second bearing, and a bushing. The motor rotor assembly is fitted onto the radial outer wall of the spindle core, forming a rotor cooling channel between them. The motor stator assembly is assembled into the radial inner wall of the bushing, forming a stator cooling channel between them. The first bearing housing contains a bearing cooling channel. The rotor cooling channel, stator cooling channel, and bearing cooling channel are interconnected. This invention simultaneously forms interconnected rotor cooling channels, stator cooling channels, and bearing cooling channels within the electric spindle, thereby effectively cooling the motor rotor assembly, motor stator assembly, and first bearing of the electric spindle, improving the cooling effect of the electric spindle, effectively reducing the temperature rise of the electric spindle, and thus ensuring the operational reliability of the electric spindle.

Description

Technical Field

[0001] This utility model belongs to the field of electric spindle design technology, specifically relating to an electric spindle and a machine tool using it. Background Technology

[0002] An electric spindle is a new technology that integrates the machine tool spindle and spindle motor into one unit. The spindle is directly driven by the built-in motor, eliminating the gear, belt, or coupling transmission of traditional spindles, thus shortening the transmission chain length of the machine tool spindle to zero. It is widely used in the manufacturing of precision molds, automobiles, ships, aerospace, and other cutting-edge products. The electric spindle has a complex structure, with the spindle core being the core component. Bearings, motors, and other parts are assembled on it, and the overall assembly precision determines the rotational accuracy of the electric spindle.

[0003] The main factor affecting the lifespan of an electric spindle is the cooling efficiency of the motor and bearing housing. During operation, the motor and bearings generate a lot of heat. If the motor and bearings cannot be cooled quickly, their temperature will rise rapidly, eventually causing permanent damage and rendering them unusable.

[0004] Currently, electric spindles primarily use water cooling. However, the cooling channel has low efficiency, and the short water circulation path fails to form an effective cooling channel. The motor cooling channel cannot simultaneously cool the bearing housings and only cools the motor stator, neglecting rotor cooling, thus failing to quickly reduce the heat generated during spindle operation. For example, CN214601967U uses an axially penetrating cooling channel, resulting in fast water flow, short cooling time, and low cooling efficiency. Similarly, CN118321585A, with its bidirectional adjustable flow rate spindle stator cooling device, cannot cool the motor rotor. Utility Model Content

[0005] Therefore, this utility model provides an electric spindle and a machine tool using it, which can overcome the technical problems of insufficient cooling and low cooling efficiency caused by the inability of the cooling structure of the electric spindle in related technologies to simultaneously cool the motor stator, rotor and bearings.

[0006] To address the aforementioned problems, this utility model provides an electric spindle, comprising a spindle core, a motor rotor assembly, a motor stator assembly, a first bearing housing and a first bearing assembled thereon, a second bearing housing and a second bearing assembled thereon, and a bushing. The first bearing and the second bearing are respectively used to support the two ends of the spindle core. The motor rotor assembly is fitted onto the radial outer wall of the spindle core, forming a rotor cooling channel between the two. The motor stator assembly is assembled into the radial inner wall of the bushing, forming a stator cooling channel between the two. A bearing cooling channel is constructed within the first bearing housing. The rotor cooling channel, the stator cooling channel, and the bearing cooling channel are interconnected.

[0007] In some embodiments, the stator cooling channel is constructed on the radial inner wall surface of the bushing; and / or, the rotor cooling channel is constructed on the radial outer wall surface of the shaft core.

[0008] In some embodiments, the stator cooling channel is a double-helix channel extending around the axis of the bushing; and / or, the rotor cooling channel is a double-helix channel extending around the axis of the shaft core; and / or, the bearing cooling channel extends axially along the shaft core.

[0009] In some embodiments, the electric spindle further includes a flow channel, which includes a first flow channel and a second flow channel. The first flow channel is formed on a first end of the spindle core and extends axially along the spindle core. The first flow channel communicates with a first port of the rotor cooling channel. The second flow channel is formed in the first bearing housing and extends radially along the spindle core. A cooling fluid inlet is formed on the outer peripheral wall of the bushing and communicates with the inlet end of the stator cooling channel. The cooling fluid inlet can communicate with the first flow channel via the second flow channel.

[0010] In some embodiments, the stator cooling channel includes a first stator channel and a second stator channel, the first stator channel and the second stator channel forming the double helical channel; the rotor cooling channel includes a first rotor channel and a second rotor channel, the first rotor channel and the second rotor channel forming the double helical channel; two bearing cooling channels are provided; two sets of cooling fluid inlets and flow-through channels are respectively provided one-to-one; one set is connected to the first stator channel, the first rotor channel, and one bearing cooling channel; the other set is connected to the second stator channel, the second rotor channel, and another bearing cooling channel.

[0011] In some embodiments, when the electric spindle is in use, the height of the first bearing housing is lower than the height of the second bearing housing. With the orientation of the electric spindle in the use state as a reference, a cooling fluid outlet is formed on the top end face of the bushing, and the cooling fluid in the rotor cooling channel can flow to the cooling fluid outlet through the overflow communication channel.

[0012] In some embodiments, two first bearings are disposed on the first bearing housing.

[0013] In some embodiments, the motor rotor assembly includes a rotor core, the two ends of the shaft hole of the rotor core having a first sealing ring protruding radially inward, the first sealing ring being clamped between the first sealing ring and the radial outer wall surface of the shaft core; and / or, the motor stator assembly includes a stator core, the two ends of the stator core having a second sealing ring protruding radially outward, the second sealing ring being clamped between the second sealing ring and the radial inner wall surface of the bushing.

[0014] In some embodiments, the shaft core includes a first shaft segment, a second shaft segment, and a third shaft segment continuously arranged along its axial direction, wherein the outer diameter of the second shaft segment is larger than the outer diameters of the first and third shaft segments, the rotor cooling channel is formed on the second shaft segment, and two first sealing ring platforms are respectively fitted onto the radial outer walls of the first and second shaft segments; and / or, the bushing includes a first cylindrical segment, a second cylindrical segment, and a third cylindrical segment continuously arranged along its axial direction, wherein the inner diameter of the second cylindrical segment is smaller than the inner diameters of the first and third cylindrical segments, the stator cooling channel is formed on the second cylindrical segment, and two second sealing ring platforms are respectively fitted onto the radial inner walls of the first and second cylindrical segments.

[0015] This utility model also provides a machine tool, including the above-mentioned electric spindle.

[0016] The electric spindle and the machine tool using it provided by this utility model have the following beneficial effects:

[0017] The rotor cooling channel, stator cooling channel and bearing cooling channel are simultaneously formed in the electric spindle, which can effectively cool the motor rotor assembly, motor stator assembly and first bearing of the electric spindle, improve the cooling effect of the electric spindle, effectively reduce the temperature rise of the electric spindle, and thus ensure the operational reliability of the electric spindle.

[0018] The rotor cooling channel and the stator cooling channel are respectively constructed on the radial outer wall surface of the shaft core and the radial inner wall surface of the shaft sleeve. The stator core and the rotor core only serve as the sealing wall surface of the aforementioned channels, which can reduce the processing difficulty of directly constructing the corresponding channels on the wall surface of the silicon steel lamination.

[0019] Using double-helix flow channels for both stator and rotor cooling channels can greatly increase the contact area between the cooling fluid and the motor rotor or stator assembly, thereby improving the cooling effect. Compared with the traditional single-helix flow channel, it can also increase the contact time between the cooling fluid and the heat source structure, which can also improve the cooling effect.

[0020] The cooling fluid entering through the cooling fluid inlet can enter the second flow channel that extends radially within the first bearing housing and then pass through the rotor cooling channel. The second flow channel and the bearing cooling channel together form a double-sided cooling of the first bearing on the radially outer side and the axial end face, which can improve the cooling effect on the first bearing.

[0021] Since a bearing cooling channel extending axially and a second flow channel extending radially are simultaneously formed in the first bearing, the heat dissipation and cooling requirements of multiple first bearings can be met.

[0022] By setting up two parallel and relatively independent cooling channels, it is possible to further achieve comprehensive and balanced cooling of the motor stator assembly, motor rotor assembly and the first bearing;

[0023] Since the electric spindle is used vertically, only one port is provided at the bottom of the rotor cooling channel. This allows the pressure within the cooling channel to force the cooling fluid upwards into the rotor cooling channel, while some of the entering cooling fluid flows downwards under its own weight. This creates a counter-current flow of the entering and exiting cooling fluids within the rotor cooling channel, significantly improving the cooling effect on the motor rotor assembly. Furthermore, the cooling fluid that has exchanged heat with the motor rotor assembly can flow back through the aforementioned stator cooling channel and exit through the cooling fluid outlet, achieving secondary recycling of the cooling fluid. It is particularly important to emphasize that placing the cooling fluid outlet on the top end face of the bushing allows the cooling fluid flowing out of the stator cooling channel to simultaneously dissipate heat from the second bearing, further enhancing the cooling effect on the electric spindle. Attached Figure Description

[0024] To more clearly illustrate the embodiments of this utility model 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. 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.

[0025] Figure 1 This is a schematic diagram of the cross-section of the electric spindle according to an embodiment of the present invention;

[0026] Figure 2 yes Figure 1 A three-dimensional structural diagram (exploded view) of the electric spindle in the diagram;

[0027] Figure 3 It is Figure 1The diagram shows a three-dimensional structure of the cooling channels extracted from the electric spindle. To make it clearer, the positions of the rotor cooling channels and stator cooling channels in the diagram have been changed from coaxial assembly to axial spacing. The arrows in the diagram indicate the flow path of the cooling fluid.

[0028] Figure 4 yes Figure 1 A schematic diagram of the axial section of the shaft core;

[0029] Figure 5 yes Figure 1 A three-dimensional structural diagram of the shaft core;

[0030] Figure 6 yes Figure 1 A three-dimensional structural diagram of the rotor assembly of the electric motor (only the rotor core is shown, and other structures such as magnets are not shown);

[0031] Figure 7 yes Figure 6 A schematic diagram of the axial cross-section of the rotor core.

[0032] The attached figures are labeled as follows:

[0033] 1. Shaft core; 11. First flow channel; 2. Motor rotor assembly; 21. First sealing ring platform; 3. Motor stator assembly; 31. Second sealing ring platform; 4. First bearing housing; 41. First bearing; 42. Second flow channel; 5. Second bearing housing; 51. Second bearing; 6. Shaft sleeve; 61. Cooling fluid inlet; 62. Cooling fluid outlet; 71. Rotor cooling channel; 72. Stator cooling channel; 73. Bearing cooling channel. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, 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 utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0035] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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 utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0036] 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° or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0037] 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 cannot be construed as limiting the scope of protection of this utility model.

[0038] See also Figures 1 to 7As shown, according to an embodiment of the present invention, an electric spindle is provided, including a spindle core 1, a motor rotor assembly 2, a motor stator assembly 3, a first bearing housing 4 and a first bearing 41 assembled thereon, a second bearing housing 5 and a second bearing 51 assembled thereon, and a bushing 6. The first bearing 41 and the second bearing 51 are respectively used to support the two ends of the spindle core 1, that is, the spindle core 1 is rotatably supported by the aforementioned first bearing 41 and second bearing 51. The motor rotor assembly 2 is fitted outside the radial outer wall of the spindle core 1 and a rotor cooling channel 71 is formed between the two for targeted cooling of the motor rotor assembly 2. The motor stator assembly 3 is assembled inside the radial inner wall of the bushing 6 and a [missing information - likely a specific structure or feature] is formed between the two. The stator cooling channel 72 is used for targeted cooling of the motor stator assembly 3. It is understood that the aforementioned motor stator assembly 3 is fitted radially outside the motor rotor assembly 2 and forms a stator-rotor air gap between the two. The aforementioned motor rotor assembly 2 specifically includes a rotor core (not labeled in the figure) and magnets (not shown in the figure) assembled thereon. The aforementioned motor stator assembly 3 specifically includes a stator core (not labeled in the figure) and stator windings (not shown in the figure) wound on each of its stator teeth. The first bearing housing 4 is constructed with a bearing cooling channel 73 for targeted cooling of the first bearing 41. The rotor cooling channel 71, stator cooling channel 72, and bearing cooling channel 73 are connected.

[0039] In this technical solution, rotor cooling channels 71, stator cooling channels 72 and bearing cooling channels 73 that are interconnected are formed in the electric spindle, thereby effectively cooling the motor rotor assembly 2, motor stator assembly 3 and first bearing 41 of the electric spindle, improving the cooling effect of the electric spindle, effectively reducing the temperature rise of the electric spindle, and thus ensuring the operational reliability of the electric spindle.

[0040] In some embodiments, the stator cooling channel 72 is constructed on the radial inner wall surface of the bushing 6; and / or, the rotor cooling channel 71 is constructed on the radial outer wall surface of the shaft core 1. In a specific embodiment, the aforementioned rotor cooling channel 71 and stator cooling channel 72 are formed by machining.

[0041] In this technical solution, the rotor cooling channel 71 and the stator cooling channel 72 are respectively constructed on the radial outer wall surface of the shaft core 1 and the radial inner wall surface of the bushing 6. The stator core and the rotor core are only used as the sealing wall surface of the aforementioned channels, which can reduce the processing difficulty of directly constructing the corresponding channels on the wall surface of the silicon steel lamination.

[0042] In some embodiments, the stator cooling channel 72 is a double-helix channel extending around the axis of the bushing 6; and / or, the rotor cooling channel 71 is a double-helix channel extending around the axis of the core 1.

[0043] In this technical solution, both the stator cooling channel 72 and the rotor cooling channel 71 adopt double spiral channels, which can greatly increase the contact area between the cooling fluid and the motor rotor assembly 2 or the motor stator assembly 3, thereby improving the cooling effect. At the same time, compared with the traditional single spiral channel, it can also increase the contact time between the cooling fluid and the heat source structure, which can also improve the cooling effect.

[0044] In some embodiments, the bearing cooling channel 73 extends axially along the shaft core 1 and covers as much as possible the axial width of the first bearing 41, ensuring a cooling effect across the full axial width of the first bearing 41.

[0045] In some embodiments, the electric spindle further includes a flow channel (not labeled in the figure), which includes a first flow channel 11 and a second flow channel 42. The first flow channel 11 is formed on a first end of the spindle core 1 and extends axially along the spindle core 1. The first flow channel 11 connects to the first port of the rotor cooling channel 71 (i.e.,...). Figure 1 The left port in the indicated direction is connected, the second flow channel 42 is formed inside the first bearing seat 4 and extends radially along the shaft core 1, and a cooling fluid inlet 61 is formed on the outer peripheral wall of the bushing 6, which is connected to the inlet end of the stator cooling channel 72. The cooling fluid inlet 61 can be connected to the first flow channel 11 via the second flow channel 42.

[0046] See details Figure 1 As shown, the cooling fluid entering through the cooling fluid inlet 61 can enter the second flow channel 42, which extends radially within the first bearing housing 4, and then pass through the rotor cooling channel 71. The second flow channel 42 and the bearing cooling channel 73 together form a double-sided cooling of the first bearing 41 on the radially outer side and the axial end face, which can improve the cooling effect of the first bearing 41.

[0047] In some embodiments, two first bearings 41 are provided on the first bearing housing 4.

[0048] In this technical solution, since a bearing cooling channel 73 extending axially and a second flow channel 42 extending radially are simultaneously formed in the first bearing housing 4, the heat dissipation and cooling requirements of multiple first bearings 41 can be met.

[0049] In some embodiments, the stator cooling channel 72 includes a first stator channel (not labeled in the figure) and a second stator channel (not labeled in the figure), the first stator channel and the second stator channel forming the double-helix channel. The rotor cooling channel 71 includes a first rotor channel (not labeled in the figure) and a second rotor channel (not labeled in the figure), the first rotor channel and the second rotor channel forming the double-helix channel. Two bearing cooling channels 73 are provided. The cooling fluid inlet 61 and the through-flow communication channels are respectively provided in two sets, one set communicating with the first stator channel, the first rotor channel, and one bearing cooling channel 73, and the other set communicating with the second stator channel, the second rotor channel, and another bearing cooling channel 73. See details below. Figure 1 As shown, the two cooling fluid inlets 61 are symmetrical about the axis of the shaft core 1 in the circumferential direction of the bushing 6, that is, the included angle between the two is 180°.

[0050] In this technical solution, two parallel and relatively independent cooling channels are set up, which can further achieve comprehensive and balanced cooling of the motor stator assembly 3, the motor rotor assembly 2 and the first bearing 41.

[0051] In some embodiments, when the electric spindle is in use, the height of the first bearing seat 4 is lower than the height of the second bearing seat 5. In a specific embodiment, the electric spindle is placed vertically. With the orientation of the electric spindle in the use state as a reference, a cooling fluid outlet 62 is formed on the top end face of the bushing 6. The cooling fluid in the rotor cooling channel 71 can flow to the cooling fluid outlet 62 through the overflow communication channel. That is, the entry and exit of the cooling fluid in the rotor cooling channel 71 are both through the bottom port of the rotor cooling channel 71.

[0052] In this technical solution, since the electric spindle is used vertically, only one port is provided at the bottom of the rotor cooling channel 71. This allows the pressure within the cooling channel to force the cooling fluid upwards into the rotor cooling channel 71. Simultaneously, some of the cooling fluid entering the rotor cooling channel 71 flows downwards under its own weight. This creates a counter-current flow of the entering and exiting cooling fluid within the rotor cooling channel 71, significantly improving the cooling effect on the motor rotor assembly 2. Furthermore, the cooling fluid that has exchanged heat with the motor rotor assembly 2 can flow back through the aforementioned stator cooling channel 72 and exit through the cooling fluid outlet 62, achieving secondary recycling of the cooling fluid. It is particularly important to emphasize that placing the cooling fluid outlet 62 on the top end face of the bushing 6 allows the cooling fluid flowing out of the stator cooling channel 72 to simultaneously dissipate heat from the second bearing 51, further enhancing the cooling effect on the electric spindle.

[0053] In one specific embodiment, the aforementioned cooling fluid can be cooling oil, but it can also be cooling water, cooling pressurized gas, or even a refrigerant.

[0054] It is understood that a cold source component (such as a cold source unit) located outside the electric spindle is also connected between the aforementioned cooling fluid inlet 61 and cooling fluid outlet 62, so as to dissipate heat from the heated cooling fluid returning through the cooling fluid outlet 62 and then input it back into the aforementioned cooling channels through the aforementioned cooling fluid inlet 61.

[0055] In some embodiments, the motor rotor assembly 2 includes a rotor core (not shown in the figure), and the two ends of the shaft hole of the rotor core have a first sealing ring platform 21 that protrudes radially inward. The first sealing ring platform 21 is clamped between the first sealing ring platform 21 and the radial outer wall surface of the shaft core 1 to ensure the sealing of the rotor cooling channel 71; and / or, the motor stator assembly 3 includes a stator core (not shown in the figure), and the two ends of the stator core have a second sealing ring platform 31 that protrudes radially outward. The second sealing ring platform 31 is clamped between the second sealing ring platform 31 and the radial inner wall surface of the bushing 6 to ensure the sealing of the rotor cooling channel 71.

[0056] In some embodiments, the shaft core 1 includes a first shaft segment (not labeled), a second shaft segment (not labeled), and a third shaft segment (not labeled) continuously arranged along its axial direction, wherein the outer diameter of the second shaft segment is larger than the outer diameters of the first and third shaft segments, the rotor cooling channel 71 is formed on the second shaft segment, and the two first sealing ring platforms 21 are respectively fitted onto the radial outer walls of the first and second shaft segments; and / or, the bushing 6 includes a first cylindrical segment (not labeled), a second cylindrical segment (not labeled), and a third cylindrical segment continuously arranged along its axial direction. The second cylindrical section (not labeled in the figure) has an inner diameter smaller than that of the first and third cylindrical sections. The stator cooling channel 72 is formed on the second cylindrical section. The two second sealing ring platforms 31 are respectively fitted onto the radial inner walls of the first and second cylindrical sections. During specific assembly, the rotor core or the bushing 6 is heated so that the size of the corresponding sealing ring platform is greater than or less than the diameter of the corresponding matching structure to achieve radial inner and outer fitting (interference fit) of the two. After assembly, the axial position of the rotor core and the stator core can also be limited.

[0057] According to an embodiment of the present invention, a machine tool is also provided, including the electric spindle described above.

[0058] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0059] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. The above description is only a preferred embodiment of this utility model. 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 this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. An electric spindle, comprising a spindle core (1), a motor rotor assembly (2), a motor stator assembly (3), a first bearing housing (4) and a first bearing (41) assembled thereon, a second bearing housing (5) and a second bearing (51) assembled thereon, and a bushing (6), wherein the first bearing (41) and the second bearing (51) are respectively used to support the two ends of the spindle core (1), characterized in that, The motor rotor assembly (2) is fitted onto the radial outer wall of the shaft core (1) and a rotor cooling channel (71) is formed between the two. The motor stator assembly (3) is assembled into the radial inner wall of the bushing (6) and a stator cooling channel (72) is formed between the two. A bearing cooling channel (73) is constructed in the first bearing housing (4). The rotor cooling channel (71), stator cooling channel (72), and bearing cooling channel (73) are connected.

2. The electric spindle according to claim 1, characterized in that, The stator cooling channel (72) is constructed on the radial inner wall surface of the bushing (6); and / or, the rotor cooling channel (71) is constructed on the radial outer wall surface of the shaft core (1).

3. The electric spindle according to claim 1, characterized in that, The stator cooling channel (72) is a double helical channel that extends around the axis of the bushing (6); and / or, the rotor cooling channel (71) is a double helical channel that extends around the axis of the shaft core (1); and / or, the bearing cooling channel (73) extends axially along the shaft core (1).

4. The electric spindle according to claim 3, characterized in that, It also includes a flow channel, which includes a first flow channel (11) and a second flow channel (42). The first flow channel (11) is formed on the first end of the shaft core (1) and extends along the axial direction of the shaft core (1). The first flow channel (11) is connected to the first port of the rotor cooling channel (71). The second flow channel (42) is formed on the first bearing seat (4) and extends radially along the shaft core (1). A cooling fluid inlet (61) is formed on the outer peripheral wall of the bushing (6) and is connected to the inlet end of the stator cooling channel (72). The cooling fluid inlet (61) can be connected to the first flow channel (11) via the second flow channel (42).

5. The electric spindle according to claim 4, characterized in that, The stator cooling channel (72) includes a first stator channel and a second stator channel, which together form the double helix channel. The rotor cooling channel (71) includes a first rotor channel and a second rotor channel, which together form the double helix channel. There are two bearing cooling channels (73). The cooling fluid inlet (61) and the flow-through channel are provided in two sets, one set of which is connected to the first stator channel, the first rotor channel, and one bearing cooling channel (73), and the other set is connected to the second stator channel, the second rotor channel, and another bearing cooling channel (73).

6. The electric spindle according to claim 5, characterized in that, When the electric spindle is in use, the height of the first bearing seat (4) is lower than the height of the second bearing seat (5). With the position of the electric spindle in the use state as a reference, a cooling fluid outlet (62) is formed on the top side end face of the bushing (6). The cooling fluid in the rotor cooling channel (71) can flow to the cooling fluid outlet (62) through the flow-through channel.

7. The electric spindle according to claim 4, characterized in that, Two first bearings (41) are provided on the first bearing housing (4).

8. The electric spindle according to claim 1, characterized in that, The motor rotor assembly (2) includes a rotor core, and the two ends of the shaft hole of the rotor core have a first sealing ring platform (21) that protrudes radially inward. The first sealing ring platform (21) is clamped between the first sealing ring platform (21) and the radial outer wall surface of the shaft core (1); and / or, the motor stator assembly (3) includes a stator core, and the two ends of the stator core have a second sealing ring platform (31) that protrudes radially outward. The second sealing ring platform (31) is clamped between the second sealing ring platform (31) and the radial inner wall surface of the bushing (6).

9. The electric spindle according to claim 8, characterized in that, The shaft core (1) includes a first shaft segment, a second shaft segment, and a third shaft segment continuously arranged along its axial direction, wherein the outer diameter of the second shaft segment is larger than the outer diameter of the first shaft segment and the third shaft segment, the rotor cooling channel (71) is formed on the second shaft segment, and the two first sealing ring platforms (21) are respectively fitted onto the radial outer walls of the first shaft segment and the second shaft segment; and / or, the bushing (6) includes a first cylindrical segment, a second cylindrical segment, and a third cylindrical segment continuously arranged along its axial direction, wherein the inner diameter of the second cylindrical segment is smaller than the inner diameter of the first cylindrical segment and the third cylindrical segment, the stator cooling channel (72) is formed on the second cylindrical segment, and the two second sealing ring platforms (31) are respectively fitted onto the radial inner walls of the first cylindrical segment and the second cylindrical segment.

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

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