Cooling component, resistance spindle and CNC machine tool

Abstract

The present invention provides a cooling component, comprising an inner cylinder and an outer cylinder sleeved on the outside of the inner cylinder, the outer wall surface of the inner cylinder is provided with a plurality of inner grooves distributed along the circumferential direction, the inner wall surface of the outer cylinder is provided with a plurality of outer grooves distributed along the circumferential direction, and the number of the inner grooves is the same as the outer grooves; in the circumferential direction, the inner groove comprises a first end and a second end relative to each other, the outer grooves on both sides of the inner groove are a first outer groove and a second outer groove, the first end of the inner groove is only connected with a part of the first outer groove, and the second end of the inner groove is only connected with a part of the second outer groove, the plurality of inner grooves and the plurality of outer grooves constitute an annular cooling flow path surrounding the inner cylinder, so that the impact jet formed by the cooling liquid can have a relatively stable impact angle with the part to be impacted, thereby improving the cooling effect of the impact jet.

Description

Technical Field

[0001] The invention belongs to the technical field of electric spindles, and in particular relates to a cooling component, an electric spindle and a numerically controlled machine tool. Background Art

[0002] In the field of CNC machine tools and precision machining, the electric spindle is a key component, and its performance directly affects machining accuracy and efficiency. As machining demands continue to increase, electric spindle speeds are also increasing, leading to increasingly prominent issues with spindle overheating. High-speed operation generates significant heat within the electric spindle. If this heat cannot be dissipated effectively and promptly, the spindle temperature will rise, leading to thermal deformation, bearing damage, and other problems, seriously affecting machining quality and equipment life. To effectively control the electric spindle temperature and ensure stable operation, designing an efficient cooling system is crucial.

[0003] To improve the cooling effect of the electric spindle, existing technologies typically incorporate an impact ring and a target ring within the spindle, forming a jet chamber between the impact ring and the target ring. Within the jet chamber, a spoiler column is positioned, and coolant flows into the spoiler column in the form of a jet to enhance heat exchange. However, this solution results in a large volume of the jet chamber, and the coolant flows in an unpredictable direction within the chamber. This makes it difficult to control the angle at which the coolant impacts the spoiler column within the jet chamber, resulting in a reduction in the cooling effect of the impact jet.

[0004] How to ensure that the impingement jet formed by the coolant has a relatively stable impact angle with the part to be impacted is a key factor in improving the cooling effect of the impingement jet. Summary of the Invention

[0005] The present invention provides a cooling assembly, an electric spindle and a numerically controlled machine tool, wherein an impact jet formed by a cooling liquid can have a relatively stable impact angle with a part to be impacted, thereby improving the cooling effect of the impact jet.

[0006] The present invention provides a cooling assembly, comprising an inner cylinder and an outer cylinder sleeved outside the inner cylinder, wherein the outer wall surface of the inner cylinder is provided with a plurality of inner grooves distributed along the circumferential direction, and the inner wall surface of the outer cylinder is provided with a plurality of outer grooves distributed along the circumferential direction, and the number of the inner grooves is the same as the number of the outer grooves;

[0007] In the circumferential direction, the inner groove includes a first end and a second end opposite to each other, and the outer grooves on both sides of the inner groove are a first outer groove and a second outer groove. The first end of the inner groove is only connected to a portion of the first outer groove, and the second end of the inner groove is only connected to a portion of the second outer groove. The multiple inner grooves and the multiple outer grooves constitute an annular cooling flow path surrounding the inner cylinder.

[0008] In some embodiments, the inner wall surface of the inner groove includes a first bottom wall surface facing away from the center of the inner cylinder. In the axial projection, the midpoint of the first bottom wall surface is Q1, and the line passing through Q1 and the center of the inner cylinder is L1. The first bottom wall surface is a convex arc surface and is symmetrical about L.

[0009] and / or,

[0010] The inner wall surface of the outer groove includes a second bottom wall surface facing the center of the inner cylinder. In the axial projection, the midpoint of the second bottom wall surface is Q2, and the line passing through Q2 and the center of the outer cylinder is L2. The second bottom wall surface is a concave arc surface and is symmetrical about L2.

[0011] In some embodiments, the inner wall surface of the inner groove includes two opposite first sidewall surfaces, the first sidewall surfaces intersect the first bottom wall surface at a straight line L2, a surface passing through L2 and tangent to the first bottom wall surface is P1, and an angle α between the first sidewall surface and P1 is 80°≤α≤100°;

[0012] and / or,

[0013] In the circumferential direction, the inner wall surface of the outer groove includes two opposite second side wall surfaces, the second side wall surface intersects with the second bottom wall surface at a straight line L3, the surface passing through L3 and tangent to the second bottom wall surface is P2, and the angle between the second side wall surface and P2 is β, 80°≤β≤100°.

[0014] In some embodiments, there are multiple annular cooling channels, and the multiple annular cooling channels are distributed along the axial direction of the inner barrel.

[0015] In some embodiments, a plurality of first flow channels are provided inside the side wall of the inner tube, wherein a first end of the first flow channel leads to an end surface of the first end of the inner tube, a second end of the first flow channel communicates with the outer groove, and each first flow channel communicates with each group of the outer grooves in a one-to-one correspondence;

[0016] A second flow channel is provided inside the side wall of the outer cylinder, wherein the first end of the second flow channel is connected to the end face of the second end of the outer cylinder, and the second end of the second flow channel is connected to the inner groove, and each second flow channel is connected to each group of the inner grooves in a one-to-one correspondence; in the axial projection, the first flow channel and the second flow channel are located on both sides of the radial direction; the orientation of the first end of the inner cylinder is the same as that of the first end of the outer cylinder.

[0017] In some embodiments, in the circumferential direction, two adjacent inner grooves are connected via an inner groove provided on the outer wall surface of the inner tube, and two adjacent outer grooves are connected via an outer groove provided on the inner wall surface of the outer tube, and the annular cooling flow path includes the inner groove and the outer groove.

[0018] The present invention also provides an electric spindle, comprising an axis core, a front support assembly, a rear support assembly and the cooling assembly, wherein the front support assembly and the rear support assembly are respectively arranged at the two ends of the cooling assembly; the two ends of the axis core are passed through the support assembly and the rear support assembly.

[0019] In some embodiments, the rear support assembly includes a rear bearing seat and a fixed plate surrounding the outer circumference of the rear bearing seat, the outer circumference of the rear bearing seat is provided with a spiral groove surrounding itself, and when a first flow channel is provided, the fixed plate is provided with a first connecting hole connecting the outlet of the spiral groove and the first end of the first flow channel, and the number of the spiral grooves is the same as the number of the first flow channels and corresponds one to one.

[0020] In some embodiments, a pressure cover is provided on the side of the rear bearing seat facing away from the front support assembly, and an inlet hole corresponding to and connected to the spiral groove is provided on the pressure cover. A solenoid valve is provided in the inlet hole, and the opening of the solenoid valve is adjustable.

[0021] In some embodiments, the front support assembly includes a front bearing seat, the end face of the first end of the front bearing seat is in contact with the end face of the second end of the outer tube, and an annular groove is provided between the end face of the first end of the front bearing seat and the end face of the second end of the outer tube. When a second flow channel is provided, the second end of the second flow channel leads to the annular groove; a plurality of discharge flow channels are provided on the front bearing seat, and the inlets of the plurality of discharge flow channels lead to the annular groove, and the number of the discharge flow channels is less than the number of the second flow channels.

[0022] In some embodiments, the front support assembly also includes a front end cover, which is arranged at one axial end of the front bearing seat and connected to the front bearing seat; the front end cover is provided with a discharge hole that corresponds to and is connected to the discharge channel one by one, and a one-way valve is provided in the discharge hole. The setting of the one-way valve can prevent external liquid from entering the discharge channel from the discharge hole.

[0023] The present invention also provides a numerically controlled machine tool, comprising the electric spindle.

[0024] Because the jet flows along the annular cooling channel, the coolant's flow direction within the channel remains unchanged, effectively ensuring a stable impact angle between the jet and the sidewalls of the inner and outer grooves. Also, because the flow direction remains constant, the coolant's flow velocity within the annular cooling channel remains relatively stable while maintaining a stable pressure, enhancing the cooling effect of the impact jet on the sidewalls of the inner and outer grooves. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. The drawings described below are merely exemplary. Those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0026] Figure 1 is a cross-sectional view of an electric spindle according to an embodiment of the present invention;

[0027] Figure 2 This is an embodiment of the present invention Figure 1 Enlarged view of point A in the middle;

[0028] Figure 3 This is an embodiment of the present invention Figure 1 Enlarged view of point B in the middle;

[0029] Figure 4 This is a schematic diagram of an inner cylinder and an outer cylinder in an embodiment of the present invention when they are interference fit together;

[0030] Figure 5 This is an embodiment of the present invention Figure 4 Cross-sectional view at DD in the middle;

[0031] Figure 6 This is an embodiment of the present invention Figure 5 Cross-sectional view at point C in the middle;

[0032] Figure 7 This is an embodiment of the present invention Figure 6 The schematic diagram is a schematic diagram when an inner groove and an outer groove are provided;

[0033] Figure 8 is a schematic diagram of an impinging jet impacting a wall surface according to an embodiment of the present invention;

[0034] Figure 9 This is a perspective view of an inner cylinder according to an embodiment of the present invention;

[0035] Figure 10 This is a perspective view of an outer cylinder according to an embodiment of the present invention;

[0036] Figure 11Schematic diagram of the inner groove, outer groove, first flow channel, and second flow channel according to an embodiment of the present invention;

[0037] Figure 12 is a schematic diagram of the shaft core, rotor and bearing in an embodiment of the present invention when fitted together;

[0038] Figure 13 is a radial schematic diagram of a rear bearing seat according to an embodiment of the present invention;

[0039] The accompanying drawings are:

[0040] 1. Inner cylinder; 101. Inner groove; 102. First flow channel; 1011. First side wall; 1012. First bottom wall; 103. Inner groove; 2. Outer cylinder; 201. Outer groove; 2011. Second side wall; 2012. Second bottom wall; 202. Second flow channel; 203. Outer groove; 3. Shaft core; 301. Front bearing seat; 302. Rear bearing seat; 3021. Spiral groove; 3011. Exhaust flow channel; 4. Front end cover; 401. Annular groove; 402. Discharge hole; 5. Check valve; 6. Bearing; 701. Front locking ring; 702. Stator; 703. Rotor; 704. Thrust ring; 705. Outer spacer ring; 706. Inner spacer ring; 707. Gland; 708. Rear locking ring; 709. Annular protrusion; 710. Inlet hole; 711. Water inlet pipe; 712. Fixed plate; 713. Solenoid valve; 7012. First communication hole; DETAILED DESCRIPTION

[0041] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0043] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0044] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0045] See also Figure 1-13 As shown, according to an embodiment of the present invention, the present invention provides a cooling assembly, comprising an inner cylinder 1 and an outer cylinder 2 sleeved outside the inner cylinder 1, wherein the outer wall surface of the inner cylinder 1 is provided with a plurality of inner grooves 101 distributed along the circumferential direction, and the inner wall surface of the outer cylinder 2 is provided with a plurality of outer grooves 201 distributed along the circumferential direction, and the number of the inner grooves 101 is the same as the number of the outer grooves 201;

[0046] In the circumferential direction, the inner groove 101 includes a first end and a second end opposite to each other. The outer grooves 201 on both sides of the inner groove 101 are the first outer groove 201 and the second outer groove 201. The first end of the inner groove 101 is only connected to a portion of the first outer groove 201, and the second end of the inner groove 101 is only connected to a portion of the second outer groove 201. The multiple inner grooves 101 and the multiple outer grooves 201 constitute an annular cooling flow path surrounding the inner tube 1.

[0047] By making the first end of the inner groove 101 communicate only with a portion of the first outer groove 201, and the second end of the inner groove 101 communicate only with a portion of the second outer groove 201, the inner groove 101 and the outer groove 201 are alternately connected in sequence to form an annular cooling flow path surrounding the inner cylinder 1. The cooling liquid flows through the annular cooling channel at a velocity exceeding a preset flow rate, forming a jet. The jet flows in a stable direction (circumferentially; macroscopically, it does not change direction during flow) within the annular cooling channel. Microscopically, the coolant flows sequentially through the inner and outer grooves 101 and 201, creating a wavy flow path. This causes the coolant to impact the sidewalls of the inner and outer grooves 101 and 201 during flow, thereby increasing the convective heat transfer coefficient between the sidewalls of the inner and outer grooves 101 and 201 and the coolant, thereby enhancing the cooling effect of the coolant on the inner and outer cylinders 1 and 2 within the annular cooling channel. Simultaneously, as the coolant enters the inner and outer grooves 101 and 201 during flow, the surface area of ​​the inner wall of the annular cooling channel is significantly increased, thereby increasing the contact area between the coolant and the inner and outer cylinders 1 and 2, further enhancing the overall cooling effect of the cooling assembly and improving the efficiency of absorbing heat from the inner and outer cylinders 1 and 2. Because the jet flows along the annular cooling channel, the coolant's flow direction within the annular cooling channel (here, the flow direction refers to the coolant's macroscopic flow along the circumference of the inner barrel 1) remains constant. This effectively ensures a stable impact angle between the jet and the sidewalls of the inner groove 101 and the sidewalls of the outer groove 201. Also, because the flow direction remains constant, the coolant's flow velocity within the annular cooling channel remains relatively stable while maintaining a stable pressure, further enhancing the cooling effect of the impact jet on the sidewalls of the inner and outer grooves 101, 201.

[0048] Further, such as Figure 4 As shown, the inner tube 1 and the outer tube 2 are interference-fitted together.

[0049] Preferably, the inner wall surface of the inner groove 101 includes a first bottom wall surface 1012 facing away from the center of the inner cylinder 1. In the axial projection, the midpoint of the first bottom wall surface 1012 is Q1, and the line passing through Q1 and the center of the inner cylinder 1 is L1. The first bottom wall surface 1012 is a convex arc surface and is symmetrical about L.

[0050] and / or,

[0051] The inner wall surface of the outer groove 201 includes a second bottom wall surface 2012 facing the center of the inner tube 1. In the axial projection, the midpoint of the second bottom wall surface 2012 is Q2, and the line passing through Q2 and the center of the outer tube 2 is L2. The second bottom wall surface 2012 is a concave arc surface and is symmetrical about L2.

[0052] The inner wall surface of the inner groove 101 includes a first bottom wall surface 1012 facing away from the center of the inner tube 1. In the axial projection, the midpoint of the first bottom wall surface 1012 is Q1, and the line passing through Q1 and the center of the inner tube 1 is L1. The first bottom wall surface 1012 is a convex arc surface and is symmetrical about L; the first bottom wall surface 1012 has a guiding effect on the coolant entering the inner groove 101. By making the first bottom wall surface 1012 a convex arc surface and symmetrical about L, the coolant after being guided by the first bottom wall surface 1012 can impact the side wall of the inner groove 101 at a better angle to achieve a better impact jet heat exchange effect.

[0053] Similarly, the inner wall of the outer recess 201 includes a second bottom wall 2012 facing the center of the inner tube 1. In axial projection, the midpoint of the second bottom wall 2012 is Q2, and the line passing through Q2 and the center of the outer tube 2 is L2. The second bottom wall 2012 is a concave arc surface and is symmetrical about L2. After being guided through the second bottom wall 2012, the coolant can impact the sidewalls of the outer recess 201 at a better angle, achieving a better impact jet heat exchange effect.

[0054] Preferably, Figure 5-7 As shown, in the circumferential direction, the inner wall surface of the inner groove 101 includes two opposite first side wall surfaces 1011, the first side wall surface 1011 and the first bottom wall surface 1012 intersect at a straight line L2, a surface passing through L2 and tangent to the first bottom wall surface 1012 is P1, and an angle α between the first side wall surface 1011 and P1 is 80°≤α≤100°;

[0055] and / or,

[0056] In the circumferential direction, the inner wall surface of the outer groove 201 includes two opposite second side wall surfaces 2011, and the second side wall surface 2011 intersects with the second bottom wall surface 2012 at a straight line L3. The surface passing through L3 and tangent to the second bottom wall surface 2012 is P2, and the angle between the second side wall surface 2011 and P2 is β, 80°≤β≤100°.

[0057] By setting 80° ≤ α ≤ 100°, the cooling effect of the impinging jet generated by the coolant after being directed through the first sidewall surface 1011 is improved. Furthermore, when α = 90°, the heat transfer coefficient during jet impingement is maximized. By setting 80° ≤ α ≤ 100°, the cooling effect of the impinging jet generated by the coolant after being directed through the second sidewall surface 2011 is improved.

[0058] Explanation on how jet impact can improve the heat transfer between coolant and wall:

[0059] like Figure 8As shown in the figure, when the jet angle θ increases from 0° to 90°, the convective heat transfer coefficient between the jet medium and the wall gradually increases in the upstream direction of the jet impact area, and gradually decreases in the downstream direction. When the angle reaches a certain value, the heat transfer coefficient reaches a critical state. At this time, the upstream and downstream of the contact point between the fluid and the wall are symmetrically distributed, and the upstream and downstream areas reach the maximum heat transfer coefficient value at the same time. The distribution of the convective heat transfer coefficient along the wall also changes from an asymmetric distribution form to a symmetric distribution form. At this time, the overall heat transfer coefficient reaches the maximum value. The heat transfer coefficient formula is defined as follows according to Newton's law of cooling:

[0060]

[0061] Note: h w —local heat transfer coefficient, q w —Local heat density, T w —Initial wall temperature, T j —Initial temperature of the fluid, A—local area of ​​jet impact.

[0062] When a fluid forms a jet impact on a wall, different flow states will occur depending on the impact velocity, such as free flow, retention, boundary layer flow, etc. When the impact velocity reaches a certain value, a turbulent state may occur in the wall impact jet area (i.e., the area where the jet and the wall are in direct contact), which can be judged according to the Reynolds coefficient formula;

[0063]

[0064] Note: R e —Reynolds coefficient, ρ—fluid density, v—fluid impact instantaneous velocity, d—cross-sectional diameter of the droplet in the fluid, μ—fluid viscosity coefficient

[0065] The physical meaning of the Re value is the ratio of the droplet inertial force to the viscous force, which is a representative of the droplet fluidity. When the Re value exceeds a certain limit, that is, when v>2300μ / ρd, the fluid flow state in the wall jet area changes, and a turbulent area is formed in the wall impact area. Compared with the general state, the heat transfer coefficient of the turbulent jet area is greatly improved compared with the general jet. That is, when v>2300μ / ρd, the fluid heat transfer coefficient reaches its maximum value.

[0066] Regarding the flow state of the coolant in the annular cooling flow path of this application, when v>2300μ / ρd, θ≈90°, the jet heat transfer coefficient reaches the maximum value, and the cooling effect of the present invention is optimal, that is, α≈90°, β≈90°.

[0067] Preferably, Figure 11 As shown, there are multiple annular cooling flow paths, and the multiple annular cooling flow paths are distributed along the axial direction of the inner tube 1.

[0068] Multiple annular cooling channels are distributed along the axial direction of the inner tube 1, and the coolants in the multiple annular cooling channels do not interfere with each other. In this way, when the coolant flows in the multiple annular cooling channels, it can not only cool the inner tube 1 and the outer tube 2 more evenly as a whole, but also the condensed liquid in the multiple annular cooling channels does not interfere with each other, which is conducive to increasing the flow rate of the coolant and thereby improving the impact jet heat exchange effect.

[0069] Preferably, Figure 9-11 As shown, a plurality of first flow channels 102 are provided inside the side wall of the inner tube 1. The first ends of the first flow channels 102 lead to the end surface of the first end of the inner tube 1, and the second ends of the first flow channels 102 communicate with the outer grooves 201. Each first flow channel 102 communicates with each group of the outer grooves 201 in a one-to-one correspondence.

[0070] A second flow channel 202 is provided inside the side wall of the outer tube 2. The first end of the second flow channel 202 is connected to the end face of the second end of the outer tube 2, and the second end of the second flow channel 202 is connected to the inner groove 101. Each second flow channel 202 is connected to each group of the inner grooves 101 in a one-to-one correspondence. In the axial projection, the first flow channel 102 and the second flow channel 202 are located on both sides of the radial direction. The orientation of the first end of the inner tube 1 is the same as that of the first end of the outer tube 2.

[0071] By setting a first flow channel 102 on the side wall of the inner tube 1 and a second flow channel 202 on the side wall of the outer tube 2, the coolant can enter the first flow channel 102 from the first end of the first flow channel 102, and then flow into the inner groove 101. After entering the inner groove 101, the coolant is divided into two, and the two coolants flow in opposite directions in the circumferential direction of the inner tube 1 (that is, one coolant flows in the forward direction in the annular cooling flow path, and the other coolant flows in the reverse direction in the annular cooling flow path. It should be noted that the two coolants Although the flow directions within the annular cooling channel are opposite, this contradicts the aforementioned unchanging flow direction of the coolant within the annular cooling channel, as the directions of the two coolant flows in the annular cooling channel remain unchanged, always flowing in a direction along the circumference of the inner barrel 1. Since the first channel 102 and the second channel 202 are located on opposite sides of the radial direction, the two coolant flows converge within a certain outer groove 201, enter the second channel 202, and flow out from the second end of the second channel 202. By implementing the above-described method, the coolant flows into and out of the annular cooling channel, enabling the coolant to more evenly exchange heat with the inner barrel 1 and the outer barrel 2.

[0072] Preferably, Figure 7As shown, in the circumferential direction, the two adjacent inner grooves 101 are connected via the inner groove 103 provided on the outer wall surface of the inner tube 1, and the two adjacent outer grooves 201 are connected via the outer groove 203 provided on the inner wall surface of the outer tube 2, and the annular cooling flow path includes the inner groove 103 and the outer groove 203.

[0073] The two adjacent inner grooves 101 are connected through the inner groove 103 provided on the outer wall surface of the inner tube 1, and the two adjacent outer grooves 201 are connected through the outer groove 203 provided on the inner wall surface of the outer tube 2. The annular cooling flow path includes the inner groove 103 and the outer groove 203. When the coolant flows in the annular cooling flow path, part of the coolant flows out of the inner groove 101 and enters the inner groove 103 instead of entering the outer groove 201. Similarly, part of the coolant flows out of the outer groove 201 and enters the outer groove 203 and no longer enters the inner groove 101. Since the inner groove 101 and the outer groove 201 are alternately connected The setting ensures that part of the coolant does not collide with the side walls of the inner groove 101 and the side walls of the outer groove 201 during its flow. This ensures that when the coolant is subjected to a certain pressure, the flow rate of the coolant can be higher. The coolant has adhesion, and the coolant entering the outer groove 203 from the outer groove 201 and the coolant entering the inner groove 103 from the inner groove 101 can drive the nearby coolant to flow faster. The faster the coolant flows and the faster the speed at which it collides with the side walls of the inner groove 101 and the outer groove 201 is, the better the heat exchange effect of the impact jet is.

[0074] The present invention also provides an electric spindle, such as Figure 1 As shown, it includes an axis core 3, a front support assembly, a rear support assembly and the cooling assembly. The front support assembly and the rear support assembly are respectively arranged at the two ends of the cooling assembly; the two ends of the axis core 3 are passed through the support assembly and the rear support assembly.

[0075] The temperature of the electric spindle provided with the above-mentioned cooling assembly can be maintained within a reasonable temperature range, thereby improving the working performance of the electric spindle.

[0076] Preferably, Figure 1 As shown, the rear support assembly includes a rear bearing seat 302 and a fixed plate 712 surrounding the outer circumference of the rear bearing seat 302. The outer circumference of the rear bearing seat 302 is provided with a spiral groove 3021 surrounding itself. When a first flow channel 102 is provided, the fixed plate 712 is provided with a first connecting hole 7012 connecting the outlet of the spiral groove 3021 and the first end of the first flow channel 102. The number of the spiral grooves 3021 is the same as the number of the first flow channels 102 and corresponds one to one.

[0077] By arranging the spiral groove 3021 on the rear bearing seat 302, while ensuring the structural rigidity of the rear bearing seat 302, the coolant enters the first flow channel 102 through the spiral groove 3021, thereby realizing comprehensive cooling of the circumference of the rear bearing seat 302, and the arrangement of the spiral groove 3021 also increases the heat exchange area between the coolant and the rear bearing seat 302; the number of spiral structures is the same as the number of first flow channels 102 and corresponds one to one, which makes the coolant in each first flow channel 102 flow separately without interfering with each other.

[0078] Preferably, Figure 1 As shown, a pressure cover 707 is provided on the side of the rear bearing seat 302 facing away from the front support assembly. The pressure cover 707 is provided with an inlet hole 710 that corresponds to and is connected to the spiral groove 3021 one by one. A solenoid valve 713 is provided in the inlet hole 710, and the opening of the solenoid valve 713 is adjustable.

[0079] The heat generated by the electric spindle in the axial direction is uneven, and its own heat dissipation rate is also different. This results in different temperatures in different axial regions of the electric spindle. By providing a solenoid valve 713 within the inlet hole 710, the opening of the solenoid valve 713 can be adjusted to adjust the effective flow area of ​​the inlet hole 710. Since the inlet hole 710 corresponds one-to-one with the spiral groove 3021, the spiral groove 3021 corresponds one-to-one with the first flow channel 102, and the first flow channel 102 corresponds one-to-one with the annular cooling channel, the annular cooling channel is distributed along the axial direction. Thus, by controlling the opening of the solenoid valve 713 within each inlet hole 710, the flow rate and flow rate of the coolant in each annular cooling channel can be adjusted. The greater the flow rate and the faster the flow rate, the better the cooling and heat exchange efficiency. In the axial direction, in areas with higher temperatures and greater heat generation, the opening of the solenoid valve 713 is controlled to be increased, thereby increasing the flow rate and flow rate of the coolant in the corresponding annular cooling channel, thereby improving the heat exchange efficiency of the area corresponding to the annular cooling channel.

[0080] A pressure cover 707 is further provided at one end of the rear bearing seat 302 . The pressure cover 707 is provided with inlet holes 710 that are in one-to-one correspondence with the spiral grooves 3021 . Each inlet hole 710 is also provided with a water inlet pipe 711 .

[0081] Preferably, Figure 1As shown, the front support assembly includes a front bearing seat 301, the end face of the first end of the front bearing seat 301 is in contact with the end face of the second end of the outer tube 2, and an annular groove 401 is provided between the end face of the first end of the front bearing seat 301 and the end face of the second end of the outer tube 2. When a second flow channel 202 is provided, the second end of the second flow channel 202 leads to the annular groove 401; a plurality of discharge flow channels 3011 are provided on the front bearing seat 301, and the inlets of the plurality of discharge flow channels 3011 lead to the annular groove 401, and the number of the discharge flow channels 3011 is less than the number of the second flow channels 202.

[0082] By setting the annular groove 401, the coolant flowing out of multiple second flow channels 202 enters the annular groove 401 and is mixed and evenly heated. The evenly heated coolant enters the discharge flow channel 3011. Since the number of discharge flow channels 3011 is less than the number of second flow channels 202, the flow rate of the coolant in each discharge flow channel 3011 is greater than the flow rate in each second flow channel 202. In this way, the coolant flowing in the discharge flow channel 3011 can cool down the local part of the front bearing seat 301 more quickly (that is, for the local part of the front bearing seat 301, the flow rate of the coolant is too small and the cooling effect is poor), thereby improving the heat exchange and cooling effect of the front bearing seat 301.

[0083] Furthermore, the annular groove 401 may include a first annular groove provided on the front bearing seat 301 and a second annular groove provided on the outer cylinder 2 , and in the projection in the axial direction, the first annular groove and the second annular groove substantially completely overlap.

[0084] Preferably, Figure 1 As shown, the front support assembly also includes a front end cover 4, which is arranged at one axial end of the front bearing seat 301 and is connected to the front bearing seat 301; the front end cover 4 is provided with a discharge hole 402 which corresponds to and is connected to the discharge channel 3011 one by one, and a one-way valve 5 is provided in the discharge hole 402. The setting of the one-way valve 5 can prevent external liquid from entering the discharge channel 3011 from the discharge hole 402.

[0085] The front cover 4 can change the outflow direction of the coolant by setting the discharge hole 402, thereby performing fixed-point cooling on other objects that need to be cooled. A one-way valve 5 is set in the discharge hole 402 to prevent external liquid from entering the discharge channel 3011 through the discharge hole 402.

[0086] Furthermore, by controlling the one-way valve 5, the opening or closing of the discharge hole 402 can be controlled, thereby controlling the flow speed and flow rate of the coolant in the annular cooling channel. Then, according to the operating state and heating position of the electric spindle, the flow rate of the coolant in different annular cooling channels can be adjusted to achieve strengthening or weakening of the cooling of different areas.

[0087] like Figure 1 As shown, the electric spindle also includes: a bearing 6 supporting the shaft core 3, a front locking ring 701, a stator 702, a rotor 703, a thrust ring 704, an outer spacer ring 705, an inner spacer ring 706, a pressure cover 707, and a rear locking ring 708.

[0088] Specifically, such as Figure 2 and Figure 4 As shown, the first end of the inner cylinder 1 is provided with an annular protrusion 709 , and the first end of the outer cylinder 2 abuts against the annular protrusion 709 to limit the axial direction of the outer cylinder 2 . The first end of the inner cylinder 1 is fixed to the fixing plate 712 .

[0089] The present invention also provides a numerically controlled machine tool, comprising the electric spindle.

[0090] It is easy for those skilled in the art to understand that, under the premise of no conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A cooling assembly comprising an inner cylinder (1) and an outer cylinder (2) sleeved outside the inner cylinder (1), characterized in that: The outer wall surface of the inner cylinder (1) is provided with a plurality of inner grooves (101) distributed along the circumferential direction, and the inner wall surface of the outer cylinder (2) is provided with a plurality of outer grooves (201) distributed along the circumferential direction, and the number of the inner grooves (101) and the outer grooves (201) is the same; In the circumferential direction, the inner groove (101) includes a first end and a second end opposite to each other, the outer grooves (201) on both sides of the inner groove (101) are a first outer groove and a second outer groove, the first end of the inner groove (101) is only connected to a portion of the first outer groove, and the second end of the inner groove (101) is only connected to a portion of the second outer groove, and the plurality of inner grooves (101) and the plurality of outer grooves (201) form an annular cooling flow path surrounding the inner cylinder (1).

2. The cooling assembly according to claim 1, wherein: The inner wall surface of the inner groove (101) comprises a first bottom wall surface (1012) facing away from the center of the inner cylinder (1); in the axial projection, the midpoint of the first bottom wall surface (1012) is Q1, and the line passing through Q1 and the center of the inner cylinder (1) is L1; the first bottom wall surface (1012) is a convex arc surface and is symmetrical about L1; and / or, The inner wall surface of the outer groove (201) includes a second bottom wall surface (2012) facing the center of the inner cylinder (1); in the axial projection, the midpoint of the second bottom wall surface (2012) is Q2, and the line passing through Q2 and the center of the outer cylinder (2) is L2; ​​the second bottom wall surface (2012) is a concave arc surface and is symmetrical about L2.

3. The cooling assembly according to claim 2, wherein: In the circumferential direction, the inner wall surface of the inner groove (101) includes two opposite first side wall surfaces (1011), the first side wall surface (1011) and the first bottom wall surface (1012) intersect at a straight line L2, a surface passing through L2 and tangent to the first bottom wall surface (1012) is P1, and an angle between the first side wall surface (1011) and P1 is α, 80°≤α≤100°; and / or, In the circumferential direction, the inner wall surface of the outer groove (201) includes two opposite second side wall surfaces (2011), the second side wall surfaces (2011) intersect with the second bottom wall surface (2012) at a straight line L3, the surface passing through L3 and tangent to the second bottom wall surface (2012) is P2, and the angle between the second side wall surface (2011) and P2 is β, 80°≤β≤100°.

4. The cooling assembly according to claim 1, wherein: There are a plurality of annular cooling flow paths, and the plurality of annular cooling flow paths are distributed along the axial direction of the inner cylinder (1).

5. The cooling assembly according to claim 4, characterized in that A plurality of first flow channels (102) are provided inside the side wall of the inner cylinder (1), wherein a first end of the first flow channel (102) leads to an end surface of the first end of the inner cylinder (1), and a second end of the first flow channel (102) is communicated with the outer groove (201), and each first flow channel (102) is communicated with each group of the outer grooves (201) in a one-to-one correspondence; A second flow channel (202) is provided inside the side wall of the outer cylinder (2), the first end of the second flow channel (202) is connected to the end surface of the second end of the outer cylinder (2), the second end of the second flow channel (202) is connected to the inner groove (101), and each second flow channel (202) is connected to each group of the inner grooves (101) in a one-to-one correspondence; in the projection in the axial direction, the first flow channel (102) and the second flow channel (202) are located on both sides of the radial direction; the orientation of the first end of the inner cylinder (1) is the same as the orientation of the first end of the outer cylinder (2).

6. The cooling assembly according to any one of claims 1 to 5, characterized in that: In the circumferential direction, two adjacent inner grooves (101) are connected via an inner groove (103) provided on the outer wall surface of the inner tube (1), and two adjacent outer grooves (201) are connected via an outer groove (203) provided on the inner wall surface of the outer tube (2), and the annular cooling flow path includes the inner groove (103) and the outer groove (203).

7. An electric spindle, characterized in that: It comprises an axis core (3), a front support assembly, a rear support assembly and a cooling assembly according to any one of claims 1 to 6, wherein the front support assembly and the rear support assembly are respectively arranged at two ends of the cooling assembly; and the two ends of the axis core (3) are passed through the front support assembly and the rear support assembly.

8. The electric spindle according to claim 7, characterized in that: The rear support assembly includes a rear bearing seat (302) and a fixed disk (712) surrounding the outer peripheral surface of the rear bearing seat (302), the outer peripheral surface of the rear bearing seat (302) is provided with a spiral groove (3021) surrounding itself, and when a first flow channel (102) is provided, a first connecting hole (7012) is provided on the fixed disk (712) connecting the outlet of the spiral groove (3021) and the first end of the first flow channel (102), and the number of the spiral grooves (3021) is the same as the number of the first flow channel (102) and corresponds one to one.

9. The electric spindle according to claim 8, characterized in that: A pressure cover (707) is provided on the side of the rear bearing seat (302) facing away from the front support assembly. An inlet hole (710) corresponding to and communicating with the spiral groove (3021) is provided on the pressure cover (707). A solenoid valve (713) is provided in the inlet hole (710). The opening of the solenoid valve (713) is adjustable.

10. The electric spindle according to claim 7, characterized in that: The front support assembly includes a front bearing seat (301), the end surface of the first end of the front bearing seat (301) is in contact with the end surface of the second end of the outer cylinder (2), an annular groove (401) is provided between the end surface of the first end of the front bearing seat (301) and the end surface of the second end of the outer cylinder (2), and when a second flow channel (202) is provided, the second end of the second flow channel (202) leads to the annular groove (401); a plurality of discharge flow channels (3011) are provided on the front bearing seat (301), the inlets of the plurality of discharge flow channels (3011) lead to the annular groove (401), and the number of the discharge flow channels (3011) is less than the number of the second flow channels (202).

11. The electric spindle according to claim 10, characterized in that: The front support assembly further comprises a front end cover (4), which is arranged at one axial end of the front bearing seat (301) and is connected to the front bearing seat (301); a discharge hole (402) corresponding to and communicating with the discharge flow channel (3011) is provided on the front end cover (4), and a one-way valve (5) is provided in the discharge hole (402), and the one-way valve (5) is capable of preventing external liquid from entering the discharge flow channel (3011) from the discharge hole (402).

12. A CNC machine tool, characterized in that: The electric spindle comprises the electric spindle according to any one of claims 7 to 11.

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