A cooling jacket assembly, an electric spindle, and a CNC machine tool

Abstract

This invention provides a cooling jacket assembly, an electric spindle, and a CNC machine tool, belonging to the field of electric spindle technology. It includes a cooling jacket body with a spiral cooling channel arranged axially inside the cooling jacket body. The spiral cooling channel includes a first spiral cooling channel segment and a second spiral cooling channel segment, the spiral direction of the first spiral cooling channel segment being opposite to that of the second spiral cooling channel segment. The first spiral cooling channel segment has a starting end and a ending end, and the second spiral cooling channel segment has a starting end and a ending end. The starting end and ending end of the first spiral cooling channel are interconnected, as are the ending end and starting end of the second spiral cooling channel. In this invention, the cooling medium inside the cooling jacket assembly spontaneously circulates within the spiral cooling circuit as the spindle spindle rotates, solving the problem of thermal deformation of the spindle spindle due to heat.

Description

Technical Field

[0001] This invention relates to the field of electric spindle technology, and more particularly to a cooling sleeve assembly, an electric spindle, and a CNC machine tool. Background Technology

[0002] Electric spindle technology is one of the cutting-edge technologies in the field of CNC machine tools. It integrates the machine tool spindle and spindle motor into one unit. Compared with traditional mechanical spindles, electric spindles use an integrated spindle and rotor, replacing the traditional belt and gear transmission methods of mechanical spindles. This greatly improves the spindle's performance at high speeds and makes it more integrated and precise. In recent years, the machining field has developed rapidly, and electric spindle technology, as its core technology, has also made great progress.

[0003] With the continuous advancement and improvement of electric spindle technology, the problems it faces are becoming increasingly apparent. As a high-speed spindle component, the electric spindle's rotational speed is constantly increasing due to technological breakthroughs. Because of its compact structure, the internal motor losses and bearing friction generate a large amount of heat, leading to a "cold outside, hot inside" phenomenon in the electric spindle. The internal heating problem is serious. According to relevant experimental data, the heat generation of the electric spindle is mainly concentrated in three locations: the stator, the rotor, and the bearings. Among them, the heat generated by the spindle rotor accounts for about 1 / 3 to 1 / 2 of the total heat generation of the spindle. The heat generated by the rotor is transferred to the spindle core through the contact surface. Affected by the natural law of thermal expansion and contraction, the spindle core undergoes thermal deformation, resulting in thermal elongation of the spindle core and loss of spindle accuracy. Summary of the Invention

[0004] To overcome the problems existing in related technologies, this invention proposes a cooling jacket assembly, an electric spindle, and a CNC machine tool.

[0005] A first aspect of this invention provides a cooling jacket assembly for mounting on an electric spindle, comprising:

[0006] The cooling jacket body has a spiral cooling channel inside it along its axial direction.

[0007] The spiral cooling channel includes a first spiral cooling channel section and a second spiral cooling channel section, wherein the spiral direction of the first spiral cooling channel section is opposite to that of the second spiral cooling channel section.

[0008] The first spiral cooling channel segment has a first spiral cooling channel start end and a first spiral cooling channel end end, and the second spiral cooling channel segment has a second spiral cooling channel start end and a second spiral cooling channel end end.

[0009] The first spiral cooling channel starts at the beginning and ends at the second spiral cooling channel, and the first spiral cooling channel ends at the end and the second spiral cooling channel starts at the beginning, so that the spiral cooling channels form a closed-loop cooling circuit and the cooling medium in the first spiral cooling channel and the cooling medium in the second spiral cooling channel flow in opposite directions in the axial direction of the cooling jacket body.

[0010] In the above technical solution, the first spiral cooling channel segment and the second spiral cooling channel segment are distributed in layers in the radial direction of the cooling jacket body, and the projection of the first spiral channel on the central axis of the cooling jacket body and the projection of the second spiral cooling channel on the central axis of the cooling jacket body are intersected on the central axis of the cooling jacket body.

[0011] In the above technical solution, the cooling jacket body includes an inner cooling jacket plate, a middle cooling jacket plate, and an outer cooling jacket plate stacked from the inside to the outside.

[0012] The first spiral cooling channel segment is formed between the inner layer plate and the middle layer plate of the superimposed cooling jacket, and the second spiral cooling channel is formed between the middle layer plate and the outer layer plate of the superimposed cooling jacket.

[0013] In the above technical solution, the first spiral cooling channel section includes a first spiral groove section formed on the outer surface of the inner layer plate of the cooling jacket and a second spiral groove section formed on the inner surface of the middle layer plate of the cooling jacket. When the middle layer plate of the cooling jacket is sleeved on the outside of the inner layer plate of the cooling jacket, the first spiral groove section and the second spiral groove section cooperate to form the first spiral cooling channel section.

[0014] The second spiral cooling channel section includes a third spiral groove section formed on the outer surface of the intermediate layer plate of the cooling jacket and a fourth spiral groove section formed on the inner surface of the outer layer plate of the cooling jacket. When the outer layer plate of the cooling jacket is fitted onto the outer surface of the intermediate layer plate of the cooling jacket, the third spiral groove section and the fourth spiral groove section cooperate to form the second spiral cooling channel section.

[0015] In the above technical solution, the starting end of the first spiral cooling channel and the ending end of the second spiral cooling channel are interconnected through a first connecting channel, and the ending end of the first spiral cooling channel and the starting end of the second spiral cooling channel are interconnected through a second connecting channel.

[0016] In the above technical solution, the first connecting channel includes a first connecting groove segment that penetrates the middle layer plate of the cooling jacket. One end of the first connecting groove segment is connected to the starting end of the first spiral cooling channel, and the other end is connected to the ending end of the second spiral cooling channel.

[0017] The second connecting channel includes a second connecting groove section that penetrates the middle layer plate of the cooling jacket. One end of the second connecting groove section is connected to the end of the first spiral cooling channel, and the other end is connected to the beginning of the second spiral channel.

[0018] In the above technical solution, the middle layer of the cooling jacket is a heat insulation plate, the inner layer of the cooling jacket is interference-fitted with the middle layer of the cooling jacket, and the middle layer of the cooling jacket is interference-fitted with the outer layer of the cooling jacket.

[0019] In the above technical solution, the spiral cooling channel is filled with a gas-liquid mixed cooling medium composed of pure gas and coolant, and the gas-liquid mixing ratio of the gas-liquid mixed cooling medium is s, where 1:2≤s≤1:2.5.

[0020] In the above technical solution, the cooling jacket assembly is designed such that when the cooling jacket assembly rotates, the cooling medium in the spiral cooling channel moves from one end of the spiral cooling channel to the other end, and when the cooling jacket assembly rotates in different directions, the flow direction of the cooling medium in the spiral cooling channel is opposite.

[0021] In the above technical solution, when the cooling jacket assembly rotates, the cooling medium in the second spiral cooling channel section will generate a centrifugal force F, then:

[0022]

[0023] Where R represents the helix radius of the second spiral cooling channel section, n represents the rotational speed of the main spindle core, v represents the linear velocity of the main spindle core, and m represents the mass of the cooling medium unit.

[0024] When the cooling channel assembly rotates, the cooling medium in the second spiral cooling channel section will generate a spiral friction force f along the tangential direction of the spiral line. The magnitude and direction of the spiral friction force f are determined by the spiral angle θ.

[0025] When the helical friction force f satisfies f≥mgcotθ, the cooling medium in the second helical cooling channel section can spontaneously move from one end of the second helical cooling channel section to the other end.

[0026] In the above technical solution, the wall thickness of the inner layer plate of the cooling jacket is less than the wall thickness of the middle layer plate of the cooling jacket, and the wall thickness of the middle layer plate of the cooling jacket is less than the wall thickness of the outer layer plate of the cooling jacket.

[0027] A second aspect of the present invention provides an electric spindle, characterized in that it includes a spindle core, a rotor assembly, a spindle housing, and the aforementioned cooling sleeve assembly, wherein the cooling sleeve assembly is sleeved outside the spindle core, and the rotor assembly is sleeved outside the cooling sleeve assembly.

[0028] In the above technical solution, the spindle housing is sleeved outside the spindle core and the cooling sleeve assembly, and forms a first chamber and a second chamber that are independent of each other between the spindle core and the cooling sleeve assembly. The first chamber is used to install the front bearing assembly, the rear bearing assembly and the rotor assembly. The second chamber is used to store cooling gas to directly cool the cooling medium in the spiral cooling channel. After being cooled down, the cooling medium circulates under the radial force of the spiral cooling channel and re-enters the cooling position to achieve cyclic cooling.

[0029] The front bearing assembly is fitted outside the main spindle core, while the rear bearing assembly and rotor assembly are fitted outside the cooling sleeve assembly.

[0030] In the above technical solution, the spindle housing includes an intermediate housing, a front end cover, and a rear end cover;

[0031] The intermediate housing, the front cover, the spindle core, and the cooling sleeve assembly enclose each other to form a first chamber, and the intermediate housing, the rear cover, and the cooling sleeve assembly enclose each other to form a second chamber.

[0032] In the above technical solution, a cooling gas nozzle is provided in the second chamber for injecting cooling gas into the second chamber.

[0033] A third aspect of the present invention provides a CNC machine tool, including the electric spindle mentioned above.

[0034] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0035] 1. The cooling sleeve assembly in this invention, through the angular force generated by the internal spiral cooling channel during its rotation, drives the internal cooling medium to circulate spontaneously within the spiral cooling circuit. The cooling medium cools the heat source of the electric spindle, thus solving the problem of thermal deformation of the electric spindle core due to heat. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0037] Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of the cooling jacket assembly of the present invention;

[0038] Figure 2 This is a cross-sectional view of an embodiment of the cooling jacket assembly of the present invention;

[0039] Figure 3 for Figure 2 A schematic cross-sectional view of surface AA in the embodiment;

[0040] Figure 4 for Figure 2 A schematic cross-sectional view of the BB surface in the embodiment;

[0041] Figure 5 This is a schematic diagram of the three-dimensional structure of the spiral cooling channel obtained after removing material from the cooling jacket in an embodiment of the cooling jacket assembly of the present invention.

[0042] Figure 6 This is a schematic diagram of the stress analysis structure of the spiral cooling channel in an embodiment of the cooling component of the present invention. Figure 1 ;

[0043] Figure 7 This is a schematic diagram of the stress analysis structure of the spiral cooling channel in an embodiment of the cooling jacket assembly of the present invention. Figure 2 ;

[0044] Figure 8 This is a three-dimensional structural diagram of the spindle core in an embodiment of the electric spindle of the present invention;

[0045] Figure 9 This is a cross-sectional view of the cooling sleeve assembly mounted on the electric spindle core in an embodiment of the present invention.

[0046] Figure 10 This is a three-dimensional structural schematic diagram of an embodiment of the electric spindle of the present invention;

[0047] Figure 11 This is a cross-sectional structural schematic diagram of an embodiment of the electric spindle of the present invention.

[0048] Wherein: 1-Cooling jacket body; 11-Helical cooling channel; 111-First spiral cooling channel section; 1111-First spiral groove section; 1112-Second spiral groove section; 112-Second spiral cooling channel section; 1121-Third spiral groove section; 1141-Fourth spiral groove section; 12-Inner cooling jacket plate; 13-Intermediate cooling jacket plate; 14-Outer cooling jacket plate; 15-First connecting channel; 16-Second connecting channel; 2-Main spindle core; 3-Main spindle housing; 31-Intermediate housing; 32-Front end cover; 33-Rear end cover; 4-First chamber; 5-Second chamber; 6-Front bearing assembly; 7-Rear bearing assembly; 8-Rotor assembly; 9-Cooling gas nozzle. Detailed Implementation

[0049] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0050] Currently, the heat generated by the rotor assembly of existing electric spindles is transferred to the spindle core through the contact surface. Due to the natural law of thermal expansion and contraction, the spindle core undergoes thermal deformation, resulting in thermal elongation and loss of spindle core precision. This invention provides a cooling sleeve assembly that can be mounted on the electric spindle. This cooling sleeve assembly utilizes an internal spiral cooling channel. Under the action of the angular force generated during rotation, the cooling medium inside the spiral cooling loop spontaneously circulates. Because heat exchange is achieved through convection, the higher the spindle core rotation speed, the greater the relative velocity between the fluid and the channel surface, resulting in better convective heat transfer and cooling. This solves the problem of thermal deformation of the spindle core.

[0051] The following is in conjunction with the appendix Figure 1-11 The technical solution of this embodiment is described in detail. Unless otherwise specified, the following implementation methods and embodiments can be combined with each other.

[0052] Example

[0053] like Figures 1-7 As shown, in one aspect, an embodiment of the present invention provides a cooling jacket assembly for mounting on an electric spindle, wherein the cooling jacket assembly includes:

[0054] Cooling jacket body 1, with a spiral cooling channel 11 provided inside the cooling jacket body 1 along its axial direction;

[0055] The spiral cooling channel 11 includes a first spiral cooling channel section 111 and a second spiral cooling channel section 112, wherein the spiral direction of the first spiral cooling channel section 111 is opposite to the spiral direction of the second spiral cooling channel section 112.

[0056] The first spiral cooling channel segment 111 has a first spiral cooling channel start end and a first spiral cooling channel end end, and the second spiral cooling channel segment 112 has a second spiral cooling channel start end and a second spiral cooling channel end end.

[0057] The first spiral cooling channel starts at the beginning and ends at the second spiral cooling channel, and the first spiral cooling channel ends at the end and the second spiral cooling channel starts at the beginning, so that the spiral cooling channel 11 forms a closed-loop circulating cooling circuit and the cooling medium in the first spiral cooling channel 111 and the cooling medium in the second spiral cooling channel 112 flow in opposite directions in the axial direction of the cooling jacket body 1.

[0058] When the cooling jacket assembly is mounted on the electric spindle, the spindle core of the electric spindle can drive the cooling jacket assembly to rotate. The cooling jacket assembly, through the spiral cooling channel 11 inside, under the action of the angular force generated when it rotates, pushes the cooling medium inside it to circulate spontaneously in the spiral cooling circuit. When the spindle core rotates at high speed, the cooling medium inside the spiral cooling circuit can circulate in a directional manner along the circuit, thereby achieving the cooling effect on the spindle core.

[0059] Specifically, such as Figures 2-4 As shown, the first spiral cooling channel segment 111 and the second spiral cooling channel segment 112 are distributed in layers in the radial direction of the cooling sleeve body 1, and the projections of the first spiral channel 111 on the central axis of the cooling sleeve body 1 and the projections of the second spiral cooling channel 112 on the central axis of the cooling sleeve body 1 form an intersecting distribution on the central axis of the cooling sleeve body 1, so that when the cooling sleeve assembly is assembled on the electric spindle, it can completely cover all axial positions of the electric spindle core, thereby improving the overall cooling effect on the electric spindle core.

[0060] More specifically, such as Figure 2 As shown, the cooling jacket body 1 includes an inner cooling jacket plate 12, a middle cooling jacket plate 13, and an outer cooling jacket plate 14 stacked from the inside to the outside.

[0061] The inner cooling jacket plate 12 and the middle cooling jacket plate 13 are stacked together to form a first spiral cooling channel section 111, and the middle cooling jacket plate 13 and the outer cooling jacket plate 14 are stacked together to form a second spiral cooling channel 112.

[0062] In any of the above implementation methods, such as Figures 3-4 As shown, the first spiral cooling channel section 111 includes a first spiral groove section 1111 formed on the outer surface of the inner layer plate 12 of the cooling jacket and a second spiral groove section 1112 formed on the inner surface of the middle layer plate 13 of the cooling jacket. When the middle layer plate 13 of the cooling jacket is sleeved on the outside of the inner layer plate 12 of the cooling jacket, the first spiral groove section 1111 and the second spiral groove section 1112 cooperate to form the first spiral cooling channel section 111.

[0063] The second spiral cooling channel section 112 includes a third spiral groove section 1121 formed on the outer surface of the intermediate layer plate 13 of the cooling jacket and a fourth spiral groove section 1122 formed on the inner surface of the outer layer plate 14 of the cooling jacket. When the outer layer plate 14 of the cooling jacket is sleeved on the outer surface of the intermediate layer plate 13 of the cooling jacket, the third spiral groove section 1121 and the fourth spiral groove section 1122 cooperate to form the second spiral cooling channel section 112.

[0064] Preferably, the first spiral groove segment 1111, the second spiral groove segment 1112, the third spiral groove segment 1121 and the fourth spiral groove segment 1122 are all semi-circular cross-section spiral grooves.

[0065] In any of the above embodiments, such as Figures 3-5 As shown, the starting end of the first spiral cooling channel and the ending end of the second spiral cooling channel are interconnected through the first connecting channel 15, and the ending end of the first spiral cooling channel and the starting end of the second spiral cooling channel are interconnected through the second connecting channel 16, thereby forming a closed spiral cooling loop between the first spiral cooling channel segment 111 and the second spiral cooling channel segment 112.

[0066] Specifically, such as Figures 3-4 As shown, the first connecting channel 15 includes a first connecting groove section that penetrates the intermediate layer plate 13 of the cooling jacket, wherein one end of the first connecting groove section is connected to the starting end of the first spiral cooling channel and the other end is connected to the ending end of the second spiral cooling channel;

[0067] The second connecting channel 16 includes a second connecting groove section that penetrates the intermediate layer plate 3 of the cooling jacket, wherein one end of the second connecting groove section is connected to the end of the first spiral cooling channel and the other end is connected to the beginning of the second spiral channel.

[0068] In any of the above embodiments, the intermediate layer plate 13 of the cooling jacket is a heat insulation plate, wherein the inner layer plate 12 of the cooling jacket is interference-fitted with the intermediate layer plate 13 of the cooling jacket, and the intermediate layer plate 13 of the cooling jacket is interference-fitted with the outer layer plate 14 of the cooling jacket. The three are assembled together by a heat-fitting assembly. Specifically, the intermediate layer plate 13 of the cooling jacket is made of a material with low specific heat capacity. Because of its poor thermal conductivity, it has a good heat insulation effect, thus effectively preventing heat from the heat source from being transferred along the path of heat source (heat generated by the rotor assembly / or: heat generated by the motor assembly during operation) → cooling jacket assembly → shaft core, reducing the heating of the main shaft core in the direction of heat transfer.

[0069] In any of the above embodiments, the spiral cooling channel 11 mentioned above is filled with a gas-liquid mixed cooling medium composed of pure gas and coolant, and the gas-liquid mixing ratio of the gas-liquid mixed cooling medium is s, where 1:2≤s≤1:2.5. When the spindle core rotates at high speed, the mixed cooling medium inside the spiral cooling channel circuit can circulate directionally along the spiral cooling circuit.

[0070] In any of the above embodiments, the cooling jacket assembly is designed such that when the cooling jacket assembly rotates, the cooling medium in the spiral cooling channel 11 moves from one end of the spiral cooling channel 11 to the other end, and when the cooling jacket assembly rotates in different directions, the flow direction of the cooling medium in the spiral cooling channel 11 is opposite.

[0071] The following section uses the second spiral cooling channel 112 as an example to explain in detail how to design the cooling jacket assembly in this embodiment:

[0072] like Figures 6-7As shown, when the spindle core drives the cooling sleeve assembly to rotate forward, the cooling medium in the second spiral cooling channel section 112 will generate a large centrifugal force F, causing the cooling medium in the spiral cooling channel 11 to move relative to the wall of the spiral cooling channel. The magnitude of the centrifugal force F can be calculated according to the following formula.

[0073] Where R represents the helix radius of the second spiral cooling channel segment 112, n represents the rotational speed of the main spindle core, v represents the linear velocity of the main spindle core, and m represents the mass of the cooling medium unit.

[0074] Because there is relative movement between the two layers of the spiral cooling channel 11 (the inner layer plate 12 and the middle layer plate 13 of the cooling jacket, and the middle layer plate 13 and the outer layer plate 14 of the cooling jacket) and the internal fluid cooling medium, the cooling medium inside the spiral cooling channel 11 will be subjected to the surface pressure of the spiral cooling channel 11, generating a frictional force f along the tangential direction of the spiral line.

[0075] When the cooling channel assembly rotates, the cooling medium in the second spiral cooling channel section 112 will generate a spiral friction force f along the tangential direction of the spiral line. The magnitude and direction of the spiral friction force f are determined by the spiral angle θ.

[0076] Wherein, when the helical friction force f satisfies f≥mgcotθ, the cooling medium within the second helical cooling channel section 112 can spontaneously move from one end of the second helical cooling channel section 112 to the other end. Based on the above formula, when... When f ≥ mgcotθ, the condition is met, and the cooling medium can be made to move in a directional manner along the spiral cooling channel.

[0077] It should be noted that the above detailed description is based on the second spiral cooling channel section 112 as an example. When the first spiral cooling channel section 111 is used as an example, its design method is the same as that of the second spiral cooling channel section 112. It will not be described again in the embodiments of the present invention.

[0078] It should also be noted that the wall thickness of the inner cooling jacket plate 12 mentioned above is less than the wall thickness of the middle cooling jacket plate 13, and the wall thickness of the middle cooling jacket plate 13 is less than the wall thickness of the outer cooling jacket plate 14. The thickness of the three cooling jacket plates (inner cooling jacket plate 12, middle cooling jacket plate 13, and outer cooling jacket plate 14) is set to gradually increase from the inside out. The reason for this is that when the cooling jacket assembly is installed on the electric spindle, the outer cooling jacket plate 14 needs to be stepped to facilitate its fit with the rotor assembly. However, if the outer cooling jacket plate 14 were stepped, it would affect its strength. Therefore, the outer cooling jacket plate 14 needs to be thicker. The middle cooling jacket plate 13 is thicker than the inner cooling jacket plate 13. A connecting channel (first connecting channel 15 and second connecting channel 16) needs to be opened through the intermediate layer plate 13 of the cooling jacket. Therefore, the strength of the intermediate layer plate 13 of the cooling jacket will also be affected to a certain extent. Therefore, the intermediate layer plate 13 of the cooling jacket needs to be made thicker. The inner layer plate 12 of the cooling jacket only needs to have a spiral cooling groove section on its outer layer. Therefore, its strength will not be greatly affected. Therefore, it is not necessary to make the inner layer plate 12 of the cooling jacket too thick, thus ensuring the overall strength of the cooling jacket assembly without increasing the overall structural thickness of the electric spindle assembly when the cooling jacket assembly is installed on the electric spindle.

[0079] On the other hand, the embodiments of the present invention also provide a method such as Figures 8-11 The electric spindle shown includes a spindle core 2, a rotor assembly 8, a spindle housing 3, and the aforementioned cooling sleeve assembly. The cooling sleeve assembly is fitted outside the spindle core 2, and the rotor assembly 8 is fitted outside the cooling sleeve assembly. The cooling sleeve assembly is positioned by a groove on the left end face of the spindle core 2, and is pressed on the right side by a pressure ring and then locked and fixed with a lock nut.

[0080] In any of the above embodiments, such as Figure 11 As shown, the spindle housing 3 is sleeved on the outside of the spindle core 2 and the cooling sleeve assembly, and forms a first chamber 4 and a second chamber 5 that are independent of each other between the spindle core 2 and the cooling sleeve assembly. The first chamber 4 is used to install the front bearing assembly 6, the rear bearing assembly 7 and the rotor assembly 8. The second chamber 5 is used to store cooling gas to directly cool the cooling medium in the spiral cooling channel. After being cooled down, the cooling medium circulates under the radial force of the spiral cooling channel and re-enters the cooling position to achieve cyclic cooling.

[0081] The front bearing assembly 6 is fitted outside the main shaft core 2, while the rear bearing assembly 7 and the rotor assembly 8 are fitted outside the cooling sleeve assembly.

[0082] In any of the above embodiments, such as Figure 10 and Figure 11As shown, the spindle housing 3 includes an intermediate housing 31, a front end cover 32, and a rear end cover 33;

[0083] The intermediate housing 31, the front cover 32, the main spindle core 2 and the cooling sleeve assembly form a first chamber 4, and the intermediate housing 31, the rear cover 33 and the cooling sleeve assembly form a second chamber 5.

[0084] In any of the above embodiments, the second chamber 5 is further provided with a cooling gas nozzle 9, which is used to inject cooling gas into the second chamber 5 so that the second chamber 5 is filled with cooling gas, thereby realizing heat exchange with the cooling jacket assembly and thus realizing heat dissipation of the electric spindle.

[0085] like Figure 11 As shown above, when the electric spindle rotates forward, the frictional force generated by the cooling medium in the cooling sleeve assembly can cause the cooling medium in the second spiral cooling channel section 112 to move spontaneously from the left end to the right end of the spindle core 2 along its spiral path. Conversely, because the spiral direction of the first spiral cooling channel section 111 changes, the direction of frictional force is opposite to that of the second spiral cooling channel section 112. Therefore, the cooling medium inside the first spiral cooling channel section 111 moves spontaneously from the right end to the left end of the spindle core 2 along its spiral path.

[0086] Similarly, when the spindle reverses, under the action of dual forces, the cooling medium inside the second spiral cooling channel section 112 (i.e. the outer spiral cooling channel section) moves spontaneously from the left end to the right end of the spindle core 2 along its spiral path, and the cooling medium inside the first spiral cooling channel section 111 (i.e. the inner spiral cooling channel section) moves spontaneously from the right end to the left end of the spindle core 2 along its spiral path.

[0087] The inner and outer double-layer bidirectional spiral cooling channels enable the cooling medium inside the cooling sleeve assembly to circulate back and forth from the left end to the right end, regardless of whether the electric spindle rotates forward or backward. At this time, the second chamber 5 located on the right side of the spindle core is filled with low-temperature cooling gas, which cools the right end of the spindle core 2, i.e., the right end of the cooling sleeve assembly. Since the rotor assembly, bearings, and stator, which are the heating positions of the electric spindle, are all located in the middle and slightly to the left of the spindle core 2, the cooling medium inside the cooling sleeve assembly can carry the heat from the heat source to the second chamber 5 at the right end of the spindle core 2 for heat exchange when it spontaneously circulates from the left end to the right end of the spindle core 2. After the cooling medium inside the cooling sleeve assembly is cooled by heat exchange in the second chamber 5, it continues to circulate to the left end of the spindle core 2, forming a directional heat transfer along the heat source → cooling medium → second chamber, thereby achieving the cooling of the spindle core 2.

[0088] It is worth noting that at the heat source location (i.e., the rotor and bearings), heat follows the principle of flowing from high-temperature objects to low-temperature objects, transferring heat to the outer layer plate 14 of the cooling jacket. At this time, due to the relative flow between the fluid inside the cooling jacket and the surface of the cooling channel, convective heat transfer occurs, and the heat is transferred to the cooling medium in the spiral cooling channel 11. The heat flows with the cooling medium in the spiral cooling channel 11 to the second chamber 5 at the end (i.e., the cooling chamber), where the heat flows from the high-temperature region to the low-temperature region. Then, the cooling medium returns to the heat source location, repeating the above process to achieve directional heat transfer. Since convective heat transfer is affected by the relative velocity of the fluid, the higher the spindle core speed, the greater the relative velocity between the fluid and the surface of the spiral cooling channel 11, resulting in better convective heat transfer and cooling effect.

[0089] Furthermore, this embodiment of the invention also provides a CNC machine tool, which includes the aforementioned electric spindle, thereby improving the machining accuracy of the CNC machine tool.

[0090] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0091] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0092] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0093] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A cooling jacket assembly for mounting on an electric spindle, characterized in that, include: Cooling jacket body (1), wherein a spiral cooling channel (11) is provided inside the cooling jacket body (1) along its axial direction; The spiral cooling channel (11) includes a first spiral cooling channel section (111) and a second spiral cooling channel section (112), wherein the spiral direction of the first spiral cooling channel section (111) is opposite to the spiral direction of the second spiral cooling channel section (112); The first spiral cooling channel segment (111) has a first spiral cooling channel start end and a first spiral cooling channel end end, and the second spiral cooling channel segment (112) has a second spiral cooling channel start end and a second spiral cooling channel end end; The first spiral cooling channel starts at the beginning and ends at the second spiral cooling channel, and the first spiral cooling channel ends at the end and the second spiral cooling channel starts at the beginning, so that the spiral cooling channel (11) forms a closed-loop cooling circuit and the cooling medium in the first spiral cooling channel section (111) and the cooling medium in the second spiral cooling channel section (112) flows in opposite directions in the axial direction of the cooling jacket body (1).

2. The cooling jacket assembly according to claim 1, characterized in that, The first spiral cooling channel segment (111) and the second spiral cooling channel segment (112) are distributed in layers in the radial direction of the cooling jacket body (1), and the projection of the first spiral cooling channel segment (111) on the central axis of the cooling jacket body (1) and the projection of the second spiral cooling channel segment (112) on the central axis of the cooling jacket body (1) form an intersecting distribution on the central axis of the cooling jacket body (1).

3. The cooling jacket assembly according to claim 2, characterized in that, The cooling jacket body (1) includes an inner cooling jacket plate (12), a middle cooling jacket plate (13), and an outer cooling jacket plate (14) stacked from the inside to the outside. The first spiral cooling channel segment (111) is formed between the inner layer plate (12) and the middle layer plate (13) of the cooling jacket, which are stacked together, and the second spiral cooling channel segment (112) is formed between the middle layer plate (13) and the outer layer plate (14) of the cooling jacket.

4. The cooling jacket assembly according to claim 3, characterized in that, The first spiral cooling channel section (111) includes a first spiral groove section (1111) formed on the outer surface of the inner layer plate (12) of the cooling jacket and a second spiral groove section (1112) formed on the inner surface of the middle layer plate (13) of the cooling jacket. When the middle layer plate (13) of the cooling jacket is sleeved on the outside of the inner layer plate (12) of the cooling jacket, the first spiral groove section (1111) and the second spiral groove section (1112) cooperate to form the first spiral cooling channel section (111). The second spiral cooling channel section (112) includes a third spiral groove section (1121) formed on the outer surface of the intermediate layer plate (13) of the cooling jacket and a fourth spiral groove section (1122) formed on the inner surface of the outer layer plate (14) of the cooling jacket. When the outer layer plate (14) of the cooling jacket is fitted onto the outer surface of the intermediate layer plate (13) of the cooling jacket, the third spiral groove section (1121) and the fourth spiral groove section (1122) cooperate to form the second spiral cooling channel section (112).

5. The cooling jacket assembly according to claim 3 or 4, characterized in that, The starting end of the first spiral cooling channel and the ending end of the second spiral cooling channel are interconnected through the first connecting channel (15), and the ending end of the first spiral cooling channel and the starting end of the second spiral cooling channel are interconnected through the second connecting channel (16).

6. The cooling jacket assembly according to claim 5, characterized in that, The first connecting channel (15) includes a first connecting groove segment that penetrates the intermediate layer plate (13) of the cooling jacket. One end of the first connecting groove segment is connected to the starting end of the first spiral cooling channel, and the other end is connected to the ending end of the second spiral cooling channel. The second connecting channel (16) includes a second connecting groove section that penetrates the intermediate layer plate (13) of the cooling jacket. One end of the second connecting groove section is connected to the end of the first spiral cooling channel and the other end is connected to the beginning of the second spiral channel.

7. The cooling jacket assembly according to claim 6, characterized in that, The intermediate layer plate (13) of the cooling jacket is a heat insulation plate. The inner layer plate (12) of the cooling jacket is interference-fitted with the intermediate layer plate (13) of the cooling jacket, and the intermediate layer plate (13) of the cooling jacket is interference-fitted with the outer layer plate (14) of the cooling jacket.

8. The cooling jacket assembly according to claim 1 or 7, characterized in that, The spiral cooling channel (11) is filled with a gas-liquid mixed cooling medium composed of pure gas and coolant, and the gas-liquid mixing ratio of the gas-liquid mixed cooling medium is s, where 1:2≤s≤1:2.

5.

9. The cooling jacket assembly according to claim 1 or 7, characterized in that, The cooling jacket assembly is designed such that when the cooling jacket assembly rotates, the cooling medium in the spiral cooling channel (11) moves from one end of the spiral cooling channel (11) to the other end, and when the cooling jacket assembly rotates in different directions, the flow direction of the cooling medium in the spiral cooling channel (11) is opposite.

10. The cooling jacket assembly according to claim 9, characterized in that, When the cooling jacket assembly rotates, the cooling medium in the second spiral cooling channel section (112) will generate a centrifugal force F, then: Where R represents the helix radius of the second spiral cooling channel segment (112), n represents the rotational speed of the main spindle core, v represents the linear velocity of the main spindle core, and m represents the mass of the cooling medium unit. When the cooling jacket assembly rotates, the cooling medium in the second spiral cooling channel section (112) will generate a spiral friction force f along the tangential direction of the spiral line. The magnitude and direction of the spiral friction force f are determined by the spiral angle θ. When the spiral friction force f satisfies f≥mgcotθ, the cooling medium in the second spiral cooling channel section (112) can spontaneously move from one end of the second spiral cooling channel section (112) to the other end.

11. The cooling jacket assembly according to claim 3, characterized in that, The wall thickness of the inner layer plate (12) of the cooling jacket is less than the wall thickness of the middle layer plate (13) of the cooling jacket, and the wall thickness of the middle layer plate (13) of the cooling jacket is less than the wall thickness of the outer layer plate (14) of the cooling jacket.

12. An electric spindle, characterized in that, It includes a spindle core (2), a rotor assembly (8), a spindle housing (3), and a cooling sleeve assembly as described in any one of claims 1-11, wherein the cooling sleeve assembly is sleeved outside the spindle core (2), and the rotor assembly (8) is sleeved outside the cooling sleeve assembly.

13. The electric spindle according to claim 12, characterized in that, The spindle housing (3) is sleeved on the outside of the spindle core (2) and the cooling sleeve assembly, and forms a first chamber (4) and a second chamber (5) that are independent of each other between the spindle core (2) and the cooling sleeve assembly. The first chamber (4) is used to install the front bearing assembly (6), the rear bearing assembly (7) and the rotor assembly (8). The second chamber (5) is used to store cooling gas to directly cool the cooling medium in the spiral cooling channel. After being cooled, the cooling medium circulates under the radial force of the spiral cooling channel and re-enters the cooling position to achieve cyclic cooling. The front bearing assembly (6) is sleeved on the outside of the main shaft core (2), and the rear bearing assembly (7) and rotor assembly (8) are sleeved on the outside of the cooling sleeve assembly.

14. The electric spindle according to claim 13, characterized in that, The spindle housing (3) includes an intermediate housing (31), a front end cover (32), and a rear end cover (33); The intermediate housing (31), the front end cover (32), the main spindle core (2) and the cooling sleeve assembly enclose each other to form the first chamber (4), and the intermediate housing (31), the rear end cover (33) and the cooling sleeve assembly enclose each other to form the second chamber (5).

15. The electric spindle according to claim 14, characterized in that, The second chamber (5) is provided with a cooling gas nozzle (9) for injecting cooling gas into the second chamber (5).

16. A CNC machine tool, characterized in that, The electric spindle includes any one of claims 12-15.

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