Cooling assembly, resistor main shaft and numerical control machine tool

Abstract

The invention provides a cooling assembly which comprises an inner cylinder and an outer cylinder arranged on the outer side of the inner cylinder in a sleeving mode, a plurality of inner grooves distributed in the circumferential direction are formed in the outer wall face of the inner cylinder, a plurality of outer grooves distributed in the circumferential direction are formed in the inner wall face of the outer cylinder, and the number of the inner grooves is the same as that of the outer grooves; in the circumferential direction, the inner groove comprises a first end and a second end which are opposite to each other, the outer grooves in the two sides of the inner groove are a first outer groove and a second outer groove, the first end of the inner groove is only communicated with part of the first outer groove, and the second end of the inner groove is only communicated with part of the second outer groove. The multiple inner grooves and the multiple outer grooves form an annular cooling flow path surrounding the inner cylinder, so that a stable impact angle can be formed between impact jet flow formed by cooling liquid and a to-be-impacted part, and then the cooling effect of the impact jet flow is improved.

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 performance of the electric spindle, as a key component, directly affects the machining accuracy and efficiency. With the continuous increase in machining requirements, the speed of the electric spindle is getting higher and higher, resulting in an increasingly prominent problem of spindle heating. Under high-speed operation, a large amount of heat will be generated inside the electric spindle. If it cannot be dissipated in time and effectively, the temperature of the electric spindle will rise, which will cause problems such as thermal deformation and bearing damage, seriously affecting the machining quality and equipment life. In order to effectively control the temperature of the electric spindle and ensure its stable operation, it is very important to design an efficient cooling system.

[0003] In order to improve the cooling effect of the electric spindle, in the prior art, an impact ring and a target ring are generally arranged in the electric spindle, a jet chamber is formed between the impact ring and the target ring, a spoiler column is arranged in the jet chamber, and the coolant impacts the spoiler column in the form of a jet in the jet chamber to enhance the heat exchange effect. However, in this solution, the volume of the jet chamber is large, and the flow direction of the coolant in the jet chamber is uncertain, which makes it difficult to control the angle of the coolant impacting the spoiler column in the jet chamber, resulting in a decrease in the cooling effect of the impact jet.

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

[0005] The present invention provides a cooling component, 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 that of the outer grooves;

[0007] In the circumferential direction, the inner groove includes a first end and a second end opposite 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 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, and the plurality of inner grooves and the plurality of outer grooves form 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 tube. 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 tube 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 side wall surfaces, the first side wall surface intersects with 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 between the first side wall surface and P1 is α, 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 a plurality of the annular cooling flow paths, and the plurality of the annular cooling flow paths are distributed along the axial direction of the inner barrel.

[0015] In some embodiments, a plurality of first flow channels are disposed inside the side wall of the inner cylinder, a first end of the first flow channel leads to an end surface of the first end of the inner cylinder, 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 arranged inside the side wall of the outer cylinder, a first end of the second flow channel is connected to an end surface leading to the second end of the outer cylinder, a second end of the second flow channel leads 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 projection in the axial direction, 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 arranged on the outer wall surface of the inner tube, and two adjacent outer grooves are connected via an outer groove arranged 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 circumferential surface of the rear bearing seat, the outer circumferential surface 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, and 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, 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, and 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, 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 invention also provides a numerically controlled machine tool, comprising the electric spindle.

[0024] Since the jet flows along the annular cooling flow path, the flow direction of the coolant in the annular cooling flow path will not change, which well ensures the stability of the impact angle between the jet and the side wall of the inner groove and the side wall of the outer groove. Also, because the flow direction will not change, the coolant has a relatively stable flow rate in the annular cooling flow path when the pressure on the coolant is stable, which improves the impact jet cooling effect of the coolant on the side wall of the inner groove and the outer groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

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

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

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

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

[0030] Figure 5 The embodiment of the present invention Figure 4 Sectional view at DD in the middle;

[0031] Figure 6 The embodiment of the present invention Figure 5 Sectional view at point C in the middle;

[0032] Figure 7 The embodiment of the present invention Figure 6 A schematic diagram showing a case where an inner groove and an outer groove are provided in the schematic diagram;

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

[0034] Fig. 9 is an oblique view of an inner cylinder of an embodiment of the present invention;

[0035] Fig.10 is an oblique view of an outer cylinder of an embodiment of the present invention;

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

[0037] Fig.12 is a schematic diagram of a shaft core, a rotor and a bearing in an embodiment of the present invention when they are matched together;

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

[0039] The accompanying drawings are marked as follows:

[0040] 1. Inner cylinder; 101. Inner groove; 102. First flow channel; 1011. First side wall surface; 1012. First bottom wall surface; 103. Inner groove; 2. Outer cylinder; 201. Outer groove; 2011. Second side wall surface; 2012. Second bottom wall surface; 202. Second flow channel; 203. Outer groove; 3. Shaft core; 301. Front bearing seat; 302. Rear bearing seat; 3021. Spiral groove; 3011. Discharge flow channel; 4. front end cover; 401. annular groove; 402. discharge hole; 5. one-way 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 connecting hole; DETAILED DESCRIPTION

[0041] The following will be combined with the 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 described embodiments 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 by no means 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 creative work are within the scope of protection of the present invention.

[0042] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the 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 devices or elements 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 contours 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 here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. 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 figure. For example, if the device in the accompanying 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. If not 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 that 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 a first outer groove 201 and a 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, and the plurality of inner grooves 101 and the plurality of outer grooves 201 form an annular cooling flow path surrounding the inner tube 1.

[0047] By making the first end of the inner groove 101 only connected to a portion of the first outer groove 201, and the second end of the inner groove 101 only connected to 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 tube 1. The cooling liquid flows in the annular cooling flow path at a flow rate higher than the preset flow rate to form a jet, and the jet flows in the annular cooling flow path in a stable direction (flowing along the circumferential direction, macroscopically, without changing direction during the flow process). Microscopically, the cooling liquid flows in the inner groove 101 and the outer groove 201 in sequence, so that the flow path of the cooling liquid is wavy, which makes the cooling liquid impact the side wall of the inner groove 101 and the side wall of the outer groove 201 during the flow process, thereby improving the convective heat transfer coefficient between the side wall surface of the inner groove 101 and the outer groove 201 and the cooling liquid, thereby enhancing the cooling effect of the cooling liquid on the inner cylinder 1 and the outer cylinder 2 in the annular cooling flow path. At the same time, since the cooling liquid enters the inner groove 101 and the outer groove 201 during the flow process, the wall surface area of ​​the inner wall of the annular cooling flow path is greatly increased, thereby increasing the contact area between the cooling liquid and the inner cylinder 1 and the outer cylinder 2, thereby further improving the overall cooling effect of the cooling assembly. The efficiency of absorbing heat from the inner cylinder 1 and the outer cylinder 2 is improved. Since the jet flows along the annular cooling flow path, the flow direction of the coolant in the annular cooling flow path (the flow direction here refers to the coolant flowing along the circumferential direction of the inner cylinder 1 in a macroscopic sense) will not change, which well ensures the stability of the impact angle between the jet and the side wall of the inner groove 101 and the side wall of the outer groove 201. Also, because the flow direction will not change, the flow rate of the coolant in the annular cooling flow path is relatively stable when the pressure on the coolant is stable, which further improves the impact jet cooling effect of the coolant on the side wall surface of the inner groove 101 and the outer groove 201.

[0048] Further, such as Figure 4 As shown, the inner tube 1 and the outer tube 2 are arranged together in an interference sleeve.

[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 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.

[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 projection in the axial direction, 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 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 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. The coolant guided by the second bottom wall surface 2012 can impact the side wall of the outer groove 201 at a better angle to achieve 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 intersects with the first bottom wall surface 1012 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°;

[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 coolant after being guided by the first side wall surface 1011 on the impact jet generated by the first side wall surface 1011 is better. Further, when α=90°, the heat transfer coefficient during jet impact is the largest. By setting 80°≤α≤100°, the cooling effect of the coolant after being guided by the second side wall surface 2011 on the impact jet generated by the second side wall surface 2011 is better.

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

[0059] like Figure 8As shown in the figure, in the process of increasing the jet angle θ from 0° to 90°, in the upstream direction of the jet impact area, the convective heat transfer coefficient between the jet medium and the wall gradually increases, and in the downstream direction, the heat transfer coefficient between the jet and the wall gradually decreases. 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 simultaneously reach the maximum heat transfer coefficient value. The distribution of the convective heat transfer coefficient along the wall direction 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 according to Newton's cooling law as follows:

[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 the fluid forms a jet impact on the wall, different flow states will be generated depending on the impact speed, such as free flow, retention, boundary layer flow, etc. When the impact speed reaches a certain value, a turbulent state can be generated in the wall impact jet area (i.e. the area where the jet and the wall impact 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 droplets 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, 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 the maximum value;

[0066] Regarding the flow state of the coolant in the annular cooling flow path of the present 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, Fig.11 It is shown that 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] The plurality of annular cooling channels are distributed along the axial direction of the inner tube 1, and the coolants in the plurality of annular cooling channels do not interfere with each other; thus, when the coolant flows in the plurality of annular cooling channels, it can not only cool the inner tube 1 and the outer tube 2 as a whole more evenly, but also the condensate in the plurality of annular cooling channels does not interfere with each other, which is beneficial to increase the flow rate of the coolant, and thus improve the impact jet heat exchange effect.

[0069] Preferably, Figure 9-11 As shown, a plurality of first flow channels 102 are arranged inside the side wall of the inner tube 1, a first end of the first flow channel 102 leads to the end surface of the first end of the inner tube 1, a second end of the first flow channel 102 is connected to the outer groove 201, and each first flow channel 102 is connected to 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 cylinder 2, a first end of the second flow channel 202 is connected to an end face leading to the second end of the outer cylinder 2, a second end of the second flow channel 202 leads 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.

[0071] By setting the first flow channel 102 on the side wall of the inner tube 1 and setting the 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 the coolant enters the inner groove 101, it is divided into two. The two coolants flow in opposite directions in the circumferential direction of the inner tube 1 (that is, one coolant flows forward 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 in the annular cooling flow path are opposite, this is inconsistent with the above-mentioned unchanged flow direction of the coolant in the annular cooling flow path, because the directions of the two coolants in the annular cooling flow path are unchanged, and they always flow in one direction along the circumferential direction of the inner tube 1); since the first flow channel 102 and the second flow channel 202 are located on both sides of the radial direction; this makes the two coolants converge in a certain outer groove 201 and enter the second flow channel 202 and flow out from the second end of the second flow channel 202. Through the above method, the coolant flows into and out of the annular cooling flow path, which can make the coolant better perform uniform heat exchange on the inner tube 1 and the outer tube 2.

[0072] Preferably, Figure 7As shown, in the circumferential direction, the two adjacent inner grooves 101 are connected via the inner groove 103 arranged on the outer wall surface of the inner tube 1, and the two adjacent outer grooves 201 are connected via the outer groove 203 arranged 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 arranged on the outer wall surface of the inner tube 1, and the two adjacent outer grooves 201 are connected through the outer groove 203 arranged 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 instead of entering 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 outer groove 201 during its flow. This ensures that when the coolant is subjected to a certain pressure, the flow speed 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 speed 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, 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 3 are passed through the support assembly and the rear support assembly.

[0075] The temperature of the electric spindle provided with the above 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 channel 102 and corresponds one to one.

[0077] By providing a 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 achieving comprehensive cooling of the circumference of the rear bearing seat 302, and the provision 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 allows the coolant in each first flow channel 102 to 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, and an inlet hole 710 corresponding to and connected to the spiral groove 3021 is provided on the pressure cover 707, and 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 speed is also different, which leads to different temperatures in different areas in the axial direction of the electric spindle. By setting a solenoid valve 713 in 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 to the spiral groove 3021 one-to-one, the spiral groove 3021 corresponds to the first flow channel 102 one-to-one, the first flow channel 102 corresponds to the annular cooling flow channel one-to-one, and the annular cooling flow channel is distributed along the axial direction; in this way, by controlling the opening of the solenoid valve 713 in each inlet hole 710, the flow rate and flow velocity of the coolant in each annular cooling flow channel can be adjusted. The larger the flow rate and the faster the flow rate, the better the cooling and heat exchange efficiency. In the axial direction, in the area with higher temperature and more heat generation, the opening of the solenoid valve 713 is controlled to increase, thereby increasing the flow rate and flow velocity of the coolant in the corresponding annular cooling flow channel, and improving the heat exchange efficiency of the area corresponding to the annular cooling flow 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 corresponding to and connected 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 fitted with the end face of the second end of the outer tube 2, and an annular groove 401 is arranged 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, and when a second flow channel 202 is provided, the second end of the second flow channel 202 all leads to the annular groove 401; a plurality of discharge flow channels 3011 are arranged 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 cooling effect of the front bearing seat 301.

[0083] Further, 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 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. The one-way valve 5 is set in the discharge hole 402 to prevent external liquid from entering the discharge channel 3011 from 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, and then adjusting the flow rate of the coolant in different annular cooling channels according to the operating state and heating position of the electric spindle, so as to strengthen or weaken 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 gland 707, and a rear locking ring 708.

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

[0089] The 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, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0091] The above description is only 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 principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope 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 number of the outer grooves (201) are the same; In the circumferential direction, the inner groove (101) comprises 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, characterized in that 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 L; and / or, The inner wall surface of the outer groove (201) comprises a second bottom wall surface (2012) facing the center of the inner cylinder (1); in the projection in the axial direction, 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, characterized in that: In the circumferential direction, the inner wall surface of the inner groove (101) comprises two opposite first side wall surfaces (1011), the first side wall surface (1011) intersects with the first bottom wall surface (1012) 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 surface (2011) intersects with the second bottom wall surface (2012) at a straight line L3, a surface passing through L3 and tangent to the second bottom wall surface (2012) is P2, and an angle between the second side wall surface (2011) and P2 is β, 80°≤β≤100°.

4. The cooling assembly according to claim 1, characterized in that There are a plurality of annular cooling channels, and the plurality of annular cooling channels are distributed along the axial direction of the inner tube (1).

5. The cooling assembly according to claim 4, characterized in that A plurality of first flow channels (102) are arranged inside the side wall of the inner cylinder (1), a first end of the first flow channel (102) leads to an end surface of a first end of the inner cylinder (1), a second end of the first flow channel (102) is connected to the outer groove (201), and each first flow channel (102) is connected to 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); a first end of the second flow channel (202) is connected to an end surface of the second end of the outer cylinder (2); a 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 a 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; and 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) arranged on the outer wall surface of the inner tube (1), and two adjacent outer grooves (201) are connected via an outer groove (203) arranged 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 as described in 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 support assembly and the rear support assembly.

8. The electric spindle according to claim 7, characterized in that: The rear support assembly comprises a rear bearing seat (302) and a fixed plate (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; 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 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, and an inlet hole (710) corresponding to and connected to the spiral groove (3021) is provided on the pressure cover (707), and a solenoid valve (713) is provided in the inlet hole (710), and the opening of the solenoid valve (713) is adjustable.

10. The electric spindle according to claim 7, characterized in that: The front support assembly comprises a front bearing seat (301), the end face of the first end of the front bearing seat (301) is fitted with the end face of the second end of the outer cylinder (2), an annular groove (401) is arranged 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 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 arranged 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); the front end cover (4) is provided with a discharge hole (402) which corresponds to and is in communication with the discharge channel (3011) in a one-to-one manner, and a one-way valve (5) is arranged in the discharge hole (402); the one-way valve (5) is arranged so as to prevent external liquid from entering the discharge channel (3011) from the discharge hole (402).

12. A numerically controlled machine tool, characterized in that: The electric spindle comprises the electric spindle as claimed in any one of claims 7 to 11.

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