Heat dissipation structure of machine tool spindle

Abstract

The utility model belongs to the technical field of machining equipment, especially, relate to a heat dissipation structure of lathe main shaft, include: main shaft body, one end of main shaft body is connected with the drive system of lathe, the other end is used for installing tool rest, bearing, bearing has a plurality of and distributes in both ends of main shaft body for supporting the dead weight and processing load of main shaft body, still include: heat dissipation shell is provided with the containing space for containing main shaft in heat dissipation shell, both ends of heat dissipation shell are provided with shell end cap, directional cooling unit, directional cooling unit sets up in the inside of bearing for even injection cooling gas to bearing surface, wherein, the inner ring of bearing fixes main shaft body, the outer ring fixes heat dissipation shell, and the clearance for the circulation of cooling gas is had between shell end cap and main shaft body, between the inner and outer rings of bearing. Relative to prior art, the utility model can improve the working stability of lathe main shaft.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical processing equipment technology, and in particular relates to a heat dissipation structure for a machine tool spindle. Background Technology

[0002] A machine tool is a device used to process metal or other materials. It changes the shape, size, and surface quality of materials through cutting, grinding, drilling, milling, and other methods. A machine tool typically consists of multiple components and systems, including a spindle, tool post, worktable, drive system, and control system. The machine tool spindle is one of the most critical parts of a machine tool. It is the component responsible for carrying and rotating the cutting tool. It is usually directly connected to a motor and achieves rotational motion through a series of transmission devices (such as gears, belts, bearings, etc.). Machine tool spindles accumulate heat during prolonged operation. Cooling methods for machine tool spindles include water cooling and air cooling. However, water cooling requires complex cooling channels and is prone to coolant leakage due to seal failure, which can damage the spindle or affect machining accuracy. Traditional air cooling only dissipates heat through heat sinks, heat pipes, etc., without centralized cooling of the bearings (the main heat source), resulting in low heat dissipation efficiency. Overheating of the bearings leads to a decrease in accuracy, causing the machine tool spindle to still be prone to overheating and poor working stability. Therefore, it is necessary to make improvements. Utility Model Content

[0003] The purpose of this invention is to address the aforementioned technical problems by providing a heat dissipation structure for machine tool spindles, effectively preventing overheating and improving the operational stability of the machine tool spindles.

[0004] In view of this, the present invention provides a heat dissipation structure for a machine tool spindle, comprising: The spindle body has one end connected to the machine tool's drive system and the other end used to mount the tool post. The bearings are multiple and distributed at both ends of the spindle body to support the weight of the spindle body and the machining load; Also includes: A heat dissipation housing, wherein a receiving space for accommodating the spindle is provided inside the heat dissipation housing, and end caps are provided at both ends of the heat dissipation housing; A directional cooling unit is disposed on the inner side of the bearing to uniformly spray cooling gas onto the bearing surface; The bearing has an inner ring that fixes the main shaft and an outer ring that fixes the heat dissipation shell. There are gaps between the shell end cap and the main shaft, and between the inner and outer rings of the bearing, to allow cooling gas to flow.

[0005] In this technical solution, through the configuration of a heat dissipation shell and a directional cooling unit, external cooling gas is guided and delivered by the directional cooling unit and sprayed onto the core heat-generating area of ​​the bearing. The cooling gas is in direct contact with the bearing surface, and through convection heat transfer, it quickly absorbs the heat generated by friction during the bearing's operation, keeping the bearing temperature within a reasonable operating range. This prevents overheating from causing a decrease in the hardness of the bearing material or lubrication failure. The cooling gas (hot gas) after absorbing heat has a lower density and diffuses outward along the gaps between the inner and outer rings of the bearing and between the shell end cap and the spindle body. Compared with existing technologies, this invention can improve heat dissipation efficiency and ensure spindle accuracy: the directional cooling unit provides centralized cooling of the bearing (the main heat source of the spindle), avoiding the heat concentration problem caused by the traditional air-cooled "overall heat dissipation"; at the same time, the directional spraying of cooling gas onto the core heat-generating area significantly improves heat exchange efficiency compared to traditional air cooling, effectively preventing bearing overheating and avoiding radial runout or axial movement of the spindle due to a decrease in bearing accuracy, thereby ensuring the machining accuracy of the machine tool and improving the working stability of the machine tool spindle.

[0006] Furthermore, the above technical solution also includes: The through holes are numerous and evenly distributed on the surface of the heat dissipation shell, and the through holes are connected to the receiving space to enable natural air intake and exhaust.

[0007] In the above technical solution, the directional cooling unit further includes: An annular housing, which is positioned inside the bearing via a heat dissipation outer shell, is formed by combining a first housing and a second housing. A cooling gas flow channel is disposed in an annular housing; The nozzle has several nozzles that are evenly spaced along the circumference of the annular housing on the surface of the annular housing facing the bearing. The nozzle's input end is connected to a cooling gas channel, which is used to deliver external cooling gas to the nozzle.

[0008] Furthermore, the above technical solution also includes: A noise reduction component is disposed at the output end of the nozzle to reduce airflow noise.

[0009] In the above technical solution, the noise reduction device further includes: The mounting groove is disposed at the output end of the nozzle and extends along the axial direction of the nozzle from the output end to the input end of the nozzle. A noise-reducing housing, wherein the noise-reducing housing is disposed in a mounting groove, the noise-reducing housing is made of damping material and has an axial hole for cooling gas to pass through; The noise-reducing inner shell is a frame-like structure with multiple openings. The noise-reducing inner shell is disposed within the noise-reducing outer shell and also has axial holes for cooling gas to pass through.

[0010] The beneficial effects of this utility model are: 1. Improve heat dissipation efficiency and ensure spindle accuracy: The bearing (the main heat source of the spindle) is centrally cooled by a directional cooling unit, avoiding the heat concentration problem caused by the "overall heat dissipation" of traditional air cooling. At the same time, the cooling gas is directed to the core heat-generating area, which significantly improves the heat exchange efficiency compared with traditional air cooling. This can effectively prevent the bearing from overheating and avoid the radial runout or axial movement of the spindle caused by the decrease in bearing accuracy, thereby ensuring the machining accuracy of the machine tool (such as part dimensional tolerances and surface roughness).

[0011] 2. Avoid leakage risks and improve operational safety: Compared with water-cooled cooling structures, gas cooling eliminates the need for complex coolant flow channels and sealing structures, fundamentally avoiding coolant leakage caused by seal failure. It prevents coolant from seeping into the spindle and damaging the bearing lubrication system or corroding the spindle material, while reducing equipment downtime caused by coolant leakage, thus improving the safety and reliability of machine tool operation.

[0012] 3. Simplified structural design, reduced cost and maintenance difficulty: Components such as heat dissipation shell and directional cooling unit are all detachable (such as bolted connection, adhesive bonding), which is convenient for installation and maintenance; the cooling gas circulation relies on natural air intake and through-hole exhaust, without the need for additional air extraction or flow guiding devices, which simplifies the structure and reduces manufacturing costs; at the same time, the annular shell of the directional cooling unit adopts a split design (first shell + second shell), which facilitates the cleaning or maintenance of the cooling gas flow channel in the later stage, reducing maintenance costs.

[0013] 4. Reduce operating noise and improve environmental comfort: Traditional air cooling systems generate airflow noise of over 60dB due to concentrated airflow jets, which can affect the hearing health of operators in the long term. Through the collaborative design of noise reduction components, airflow noise can be reduced to below 50dB without affecting cooling efficiency, effectively improving the comfort of the machine tool working environment and reducing the labor intensity of operators. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of a specific embodiment of the present utility model.

[0016] Figure 2 This is a schematic diagram of the heat dissipation shell structure of this utility model.

[0017] Figure 3 This is a schematic diagram of the directional cooling unit structure of this utility model.

[0018] Figure 4 This is a schematic cross-sectional view of the annular shell structure of this utility model.

[0019] Figure 5 This is a schematic diagram of the noise reduction component of this utility model.

[0020] The markings in the diagram are as follows: 1. Spindle body; 2. Bearing; 3. Heat dissipation housing; 30. Accommodation space; 31. Housing end cap; 32. Through hole; 4. Directional cooling unit; 40. Annular housing; 401. First housing; 402. Second housing; 41. Cooling gas flow channel; 410. Annular flow channel; 411. Input flow channel; 412. Output flow channel; 42. Nozzle; 5. Noise reduction component; 50. Mounting slot; 51. Noise reduction outer housing; 52. Noise reduction inner housing; 53. Opening. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] In the description of this application, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0023] Main spindle 1 The spindle body 1 serves as the core load-bearing component. One end is connected to the machine tool's drive system (such as a motor, transmission gear set, etc.) to obtain rotational power; the other end is used to mount the tool post to drive the tool to perform cutting, grinding and other machining actions. Its axis is kept parallel or perpendicular to the machine tool's machining reference surface (to adapt to different machining requirements) to ensure the movement accuracy of the tool during machining.

[0024] The spindle body 1 is made of 40Cr alloy structural steel and has an overall stepped cylindrical structure. Both ends of the spindle body are designed with adapter structures for connection to the drive system and the tool post. Drive end (the end connected to the machine tool drive system): The outer circumferential surface of the drive end of the spindle body 1 is provided with a keyway, which is used to fix the drive system's transmission components (such as couplings and pulleys) circumferentially through a flat key, ensuring that the power of the drive system can be stably transmitted to the spindle body 1; at the same time, the end face of the drive end is provided with a positioning pin hole, which is used to achieve axial positioning with the transmission components through the positioning pin, avoiding the transmission components from shifting due to vibration during transmission, and ensuring the stability of power transmission. Tool Post End (the end used to mount the tool post): The tool post end of the spindle body 1 is provided with an inner tapered hole (such as a Morse taper hole or a BT taper hole). The tapered surface accuracy of the inner tapered hole reaches IT5 grade, which is used to achieve a tight fit with the tapered shank of the tool post. The self-locking characteristic of the tapered surface ensures the coaxiality of the tool post after installation. At the same time, the outer circumferential surface of the tool post end is provided with a locking thread. The tool post is further fixed by the locking nut to prevent the tool post from loosening during high-speed rotation or cutting, thus ensuring machining safety.

[0025] Bearing 2 Bearings 2 are used to provide support. Multiple bearings are used and distributed at both ends of the spindle body 1. The specific number can be adjusted according to the length of the spindle body 1 and the load requirements (e.g., one bearing 2 is set at each end of a short spindle body 1, and two bearings 2 are set at each end of a long spindle body 1). The inner ring of the bearing 2 is fixed to the spindle body 1 with an interference fit, and the outer ring is fixed to the heat dissipation shell 3. This not only provides stable support for the weight of the spindle body 1 and the machining load (such as cutting force and grinding force), but also ensures the high-speed rotation accuracy of the spindle body 1. At the same time, a gap is reserved between the inner and outer rings of the bearing 2 to provide a channel for the flow of cooling gas.

[0026] In this embodiment, the bearing 2 is preferably an angular contact ball bearing 2 (such as model 7208AC). The angular contact ball bearing 2 can simultaneously bear the radial load (from the radial cutting force when the part is being cut) and the axial load (from the centrifugal force and axial cutting force when the spindle rotates at high speed) generated during the operation of the spindle body 1, which is suitable for the composite load requirements of the machine tool spindle. The positioning of bearing 2 is achieved through the coordinated operation of "heat dissipation housing 3 + housing end cover 31": Radial positioning: The outer ring of bearing 2 and the inner circumferential surface of heat sink housing 3 adopt a transition fit to ensure that the outer ring is fixed while avoiding deformation of heat sink housing 3 due to interference fit; the inner circumferential surface of heat sink housing 3 is provided with an annular groove at the bearing 2 installation position, and an elastic retaining ring is embedded in the groove. The elastic retaining ring fits against the end face of the outer ring of bearing 2 to achieve radial positioning of bearing 2 and prevent bearing 2 from moving axially along heat sink housing 3. Axial positioning: The limiting protrusion on the inner surface of the end cover 31 fits tightly with the other end face of the outer ring of the bearing 2. Through the bolt connection force between the end cover 31 and the heat dissipation housing 3, the bearing 2 is axially pressed between the limiting protrusion and the elastic retaining ring, forming "bidirectional axial positioning". At the same time, the inner ring of the bearing 2 and the spindle body 1 adopt an interference fit. The stepped surface of the spindle body 1 fits with the end face of the inner ring of the bearing 2, realizing the axial positioning of the inner ring of the bearing 2 and ensuring that there is no axial movement when the inner ring of the bearing 2 rotates synchronously with the spindle body 1.

[0027] Cooling gas flow gap The clearance between the inner and outer rings of bearing 2: The size of this clearance balances "support accuracy" and "gas flow": too small a clearance will increase the resistance to cooling gas flow, affecting heat dissipation efficiency; too large a clearance will reduce the support accuracy of bearing 2, leading to increased radial runout of the spindle. In this embodiment, by selecting the radial clearance of bearing 2 (such as the clearance of group 2) that conforms to the GB / T307.1 standard, sufficient flow space for cooling gas is ensured while meeting the support accuracy requirements, and at the same time, the increased vibration and noise of bearing 2 due to excessive clearance is avoided. The gap between the end cap 31 and the main shaft 1: The diameter of the central hole of the end cap 31 is slightly larger than the outer diameter of the main shaft 1, forming an annular gap; the design of this gap must avoid "too small a gap leading to poor gas flow" or "too large a gap leading to external impurities entering the accommodating space 30". In this embodiment, the gap is matched with the size of the gap between the inner and outer rings of the bearing 2 to ensure that the cooling gas can flow smoothly.

[0028] Heat dissipation casing 3 The heat dissipation housing 3 provides a space 30 for the cooling system. It has a cylindrical structure (fitting the cylindrical structure of the spindle body 1 to ensure uniform internal space). Several screw holes are opened on both ends of the housing, which can be detachably connected to the housing end cover 31 by bolts. The housing end cover 31 has a central hole for the spindle body 1 and the transmission structure (such as pulleys and couplings) to pass through. A gap is reserved between the central hole and the spindle body 1 (for the flow of cooling gas). The inner surface of the housing end cover 31 is provided with a conventional limiting protrusion ring. The limiting protrusion ring fits against the outer ring end face of the bearing 2 to achieve axial positioning of the bearing 2, prevent the bearing 2 from axially moving during the rotation of the spindle body 1, and ensure support stability.

[0029] The heat dissipation housing 3 is generally cylindrical and made of aluminum alloy (such as 6061-T6). This material has the characteristics of low density, high thermal conductivity (about 155W / (m・K)) and strong corrosion resistance. On the one hand, the low density can reduce the overall weight of the heat dissipation structure and reduce the load on the machine tool spindle. On the other hand, the high thermal conductivity can conduct the small amount of heat diffused within the housing space 30 to the external environment through the housing wall, which helps to improve the heat dissipation effect. At the same time, the corrosion resistance of aluminum alloy can prevent the cutting fluid and lubricant from corroding the housing during machine tool processing and extend its service life. Several screw holes (e.g., 6 M8 screw holes, the number of which can be adjusted according to the diameter of the housing) are evenly distributed along the circumference on the end faces of both ends of the heat dissipation housing 3. The depth of the screw holes matches the effective engagement length of the bolts to ensure connection strength. Several through holes are opened on the end cap 31 corresponding to the screw hole positions (the diameter of the through holes is slightly larger than the outer diameter of the bolts to facilitate bolt insertion). The end cap 31 is fixed to both ends of the heat dissipation housing 3 by internal hexagonal head bolts. Flat washers and spring washers can be set between the bolts and the end cap 31. Flat washers are used to increase the contact area and prevent the surface of the end cap 31 from being damaged when the bolts are tightened. Spring washers generate preload through elastic deformation to prevent the bolts from loosening due to machine tool vibration and ensure connection stability. The end cover 31 is made of the same aluminum alloy material as the heat sink housing 3, and the machining accuracy of its center hole reaches H7 level to ensure uniform gap with the spindle body 1. In addition to the limiting protrusion ring, the inner surface of the end cover 31 is also provided with an annular sealing groove. An O-ring (such as a nitrile rubber O-ring) is embedded in the sealing groove. The O-ring fits against the end face of the heat sink housing 3 to achieve a seal between the end cover 31 and the heat sink housing 3, preventing cooling gas from leaking from the connection gap between the two and ensuring that all the cooling gas can be used to cool the bearing 2.

[0030] The inner circumferential surface of the heat dissipation shell 3 is provided with a support step and a positioning protrusion for positioning the directional cooling unit 4, as detailed below: Support step: It is set on the inner side of the bearing 2 along the axial direction of the heat dissipation shell 3, and has an annular protrusion structure. Its end face fits with the end face of the annular shell 40 of the directional cooling unit 4 to achieve axial positioning of the annular shell 40. The radial height of the support step matches the wall thickness of the annular shell 40 to ensure that the outer circumferential surface of the annular shell 40 fits with the inner circumferential surface of the heat dissipation shell 3 after installation, providing a foundation for the subsequent installation of the sealing structure. Positioning protrusions: There are 3-4 strip-shaped protrusions evenly distributed along the circumference of the heat dissipation shell 3 (the number can be adjusted according to the size of the annular shell 40). The inner surface of the protrusions fits against the outer circumferential surface of the annular shell 40 to achieve circumferential positioning of the annular shell 40, prevent the annular shell 40 from rotating with the main shaft 1 or rotating circumferentially due to airflow impact, and ensure that the nozzle 42 is always aligned with the core heat-generating area of ​​the bearing 2. The supporting steps and the position protrusions are integrally formed with the heat dissipation shell 3 (made by extrusion molding process), avoiding positioning accuracy deviation caused by welding or bonding. At the same time, the surface roughness of the supporting steps and the position protrusions is controlled below Ra1.6 to reduce friction with the annular shell 40 and facilitate the installation and disassembly of the annular shell 40.

[0031] Through hole 32 and connecting hole The through holes 32 provide a channel for the circulation of cooling gas. Several through holes 32 are evenly distributed on the surface of the heat dissipation shell 3 (alternating along the circumferential direction and the axial direction), and the through holes 32 are connected to the accommodating space 30 inside the heat dissipation shell 3. The through holes 32 are evenly distributed along the circumference and axial direction of the heat dissipation shell 3, and their positions avoid the screw holes and connecting holes of the heat dissipation shell 3 to avoid affecting the structural strength. The through holes 32 are circular in shape (high processing convenience). Preferably, the axis of the through holes 32 is set at a 45° angle with the radial direction of the heat dissipation shell 3. The advantages of this angle design are: on the one hand, it can prevent external cutting chips and dust from falling directly into the receiving space 30 through the through holes 32 under the action of gravity (chips are easy to slide to the outside along the inclined direction of the through holes 32); on the other hand, it does not hinder the flow of gas.

[0032] The number of through holes 32 is adjusted according to the length and diameter of the heat dissipation shell 3 (e.g., for a shell with a length of 300mm and a diameter of 100mm, 3 rows of through holes 32 are set along the axial direction, with 6 holes in each row) to ensure that the total flow area of ​​the through holes 32 matches the flow rate of the cooling gas, and to avoid poor exhaust due to the total flow area of ​​the through holes 32 being too small, or easy entry of external impurities due to the total flow area being too large. The connection hole is located on the circumferential surface of the heat dissipation housing 3 and is aligned with the input flow channel 411 of the directional cooling unit 4. Its diameter matches the inner diameter of the input flow channel 411 to ensure that the cooling gas can flow in smoothly. The inner side of the connection hole is provided with an internal thread (such as a G1 / 4 pipe thread) for mating with the connector of the external hose connection structure (such as an external thread quick connector) to achieve a detachable connection, which facilitates the replacement or maintenance of the hose later. A sealing gasket (such as a copper flat gasket) is provided between the connection hole and the input flow channel 411. The sealing gasket is pressed by the tightening force of the connector to prevent the cooling gas from leaking from the gap between the connection hole and the connector. Directional cooling unit 4 The directional cooling unit 4, as the core cooling execution component, is located inside the bearing 2. It is positioned by the pre-set support steps and position protrusions on the inner circumferential surface of the heat dissipation shell 3, ensuring that its relative position with the bearing 2 is fixed. The directional cooling unit 4 includes an annular shell 40, a cooling gas flow channel 41, and a nozzle 42. The annular shell 40 is composed of a first shell 401 and a second shell 402, which are detachably connected by bolts (for easy installation, maintenance, and cleaning of the internal flow channel). A sealing ring (such as a nitrile rubber sealing ring) is provided on its circumferential surface and side surface, and between the first shell 401 and the second shell 402, to achieve a seal with the inner wall of the heat dissipation shell 3, preventing the cooling gas from leaking from the gap between the annular shell 40 and the heat dissipation shell 3, and ensuring that all the cooling gas can be sprayed onto the surface of the bearing 2 through the nozzle 42. The cooling gas flow channel 41 is integrated inside the annular housing 40, including annular flow channel 410, input flow channel 411 and output flow channel 412: the annular flow channel 410 is concentrically distributed with the annular housing 40 to ensure uniform gas pressure in the flow channel; one end of the input flow channel 411 is connected to the annular flow channel 410, and the other end extends to the outer circumferential surface of the annular housing 40 and is aligned with the connection hole opened on the heat dissipation housing 3. The output end of the external cooling gas supply device (such as a vortex air pump or a high-pressure fan) is connected to the input flow channel 411 through a hose connection structure (such as a quick connector + rubber hose) to realize the input of cooling gas; there are several output flow channels 412, which are evenly distributed along the circumference of the annular flow channel 410. One end of each channel is connected to the annular flow channel 410, and the other end is connected to the input end of the nozzle 42, which is used to accurately deliver the cooling gas in the annular flow channel 410 to the nozzle 42.

[0033] The nozzles 42 are evenly spaced along the circumferential surface of the annular housing 40 facing the bearing 2. The nozzles 42 are directed towards the core heat-generating area of ​​the bearing 2, namely the contact area between the rolling element and the inner and outer rings (this area is the main heat source of the bearing 2 due to concentrated rolling and sliding friction), ensuring that the cooling gas can directly act on the highest temperature part to achieve centralized cooling. The output end of the nozzles 42 is equipped with a noise reduction component 5 to reduce the airflow noise generated when the cooling gas is injected.

[0034] Both the first housing 401 and the second housing 402 are made of polytetrafluoroethylene. The structures of the first housing 401 and the second housing 402 are symmetrical and are both semi-circular. Their splicing surfaces (end faces) are provided with positioning pin holes and bolt holes. Positioning pin holes: Two are evenly distributed along the axial direction of the splicing surface. The positioning pins enable precise positioning of the first housing 401 and the second housing 402, preventing misalignment of the annular flow channel 410 after splicing and ensuring smooth flow of cooling gas. Bolt holes: Four holes are evenly distributed around the splicing surface. The first housing 401 and the second housing 402 are fixedly connected by countersunk head hex bolts. The head of the countersunk head bolt is embedded in the countersunk hole on the surface of the housing to avoid the bolt head protruding and affecting the fit between the annular housing 40 and the heat dissipation shell 3. Sealing grooves are provided on the outer circumferential surface and the side surface of the annular housing 40: the sealing groove on the outer circumferential surface is arranged along the circumference of the annular housing 40, and an O-ring is embedded therein, fitting against the inner circumferential surface of the heat dissipation shell 3 to achieve radial sealing; the sealing groove on the side surface is arranged along the axial direction of the annular housing 40, and a rectangular sealing ring is embedded therein, fitting against the end face of the support step of the heat dissipation shell 3 to achieve axial sealing; the double sealing structure ensures that the cooling gas will not leak from the gap between the annular housing 40 and the heat dissipation shell 3, and all of it enters the nozzle 42 through the output flow channel 412. The cooling gas flow channel 41 is integrated inside the annular shell 40 and is manufactured by machining methods (such as milling and drilling). The annular flow channel 410 has a circular cross-section, and its diameter is determined according to the total flow rate of the cooling gas (the larger the flow rate, the larger the diameter). This ensures that the gas velocity in the flow channel is controlled at 10-15 m / s (this velocity range can ensure heat dissipation efficiency and avoid excessive flow velocity leading to increased airflow noise). The roughness of the inner wall of the annular flow channel 410 is controlled below Ra0.8 to reduce gas flow resistance and avoid airflow turbulence caused by rough inner wall, which would generate additional noise.

[0035] Preferably, the input channel 411 has an L-shaped structure, with one end connected to the tangential direction of the annular channel 410 (to avoid pressure loss caused by gas entering the annular channel 410 perpendicularly), and the other end extending to the outer peripheral surface of the annular shell 40, aligned with the connection hole of the heat dissipation shell 3; the cross-section of the input channel 411 is circular, and its diameter is the same as that of the annular channel 410, ensuring that the gas can flow into the annular channel 410 without obstruction; the inner wall of the input channel 411 is also smoothed to reduce airflow resistance. One end of the output channel 412 is connected to the annular channel 410, and the other end is connected to the input end of the nozzle 42. The cross-section of the output channel 412 is circular, and its diameter is determined according to the number of nozzles 42 and the flow rate requirement of a single nozzle 42 (e.g., 12 nozzles 42 correspond to 12 output channels 412, and the diameter of each output channel 412 is 3mm), to ensure that the gas flow rate of each nozzle 42 is uniform. The nozzle 42 has a cylindrical or frustum-shaped structure. Its input end is matched with the output flow channel 412, and its output end is provided with a hexagonal prism-shaped mounting groove 50 that is compatible with the noise reduction component 5. The nozzle 42 has a conical spray design. This shape allows the cooling gas to form a fan-shaped spray surface, increasing the contact area with the bearing 2 surface and avoiding insufficient local cooling. At the same time, the conical spray can control the spray range of the gas, ensuring that the cooling gas is concentrated on the core heat-generating area of ​​the bearing 2 and does not diffuse to the surrounding non-heat-generating areas, thereby improving energy utilization. The nozzles 42 are evenly distributed circumferentially along the surface of the annular housing 40 facing the bearing 2. The number of nozzles is matched with the number of rolling elements of the bearing 2 (e.g., if the 7208AC bearing 2 has 8 rolling elements, the number of nozzles 42 is set to 12). This ensures that each rolling element and its contact area with the inner and outer rings can be covered by cooling gas. The distribution radius of the nozzles 42 matches the outer diameter of the bearing 2, so that the distance between the spray nozzle and the surface of the bearing 2 is controlled at 5-8mm. This distance can ensure that the cooling gas has sufficient flow velocity when it is sprayed onto the surface of the bearing 2 (to achieve efficient heat exchange) and can also avoid the nozzles 42 colliding with the rotating bearing 2 due to being too close.

[0036] Noise Reduction Component 5 The noise reduction component 5 is integrated into the output end of the nozzle 42, including a mounting groove 50, a noise reduction outer shell 51, and a noise reduction inner shell 52. The mounting groove 50 is located at the output end of the nozzle 42 and extends axially from the output end to the input end along the nozzle 42. It is hexagonal in shape (fitting the noise reduction outer shell 51 and the noise reduction inner shell 52 to ensure installation stability). The noise reduction outer shell 51 is made of open-cell polyurethane foam (a damping material) and is fixed in the mounting groove 50 by conventional bonding methods (such as high-temperature epoxy adhesive). It has axial holes inside for cooling gas to pass through. The damping material can absorb airflow vibration through its own porous structure to reduce noise generation. The noise reduction inner shell 52 is frame-shaped, consisting of a main body and an expansion joint integrally formed on both sides of the main body. The opening is also hexagonal prism in shape and is coaxially distributed with the noise-reducing outer shell 51. Openings 53 are evenly spaced along the axial and circumferential directions on each prism surface of the main body, penetrating the inner and outer surfaces. The ratio of the total area of ​​the openings 53 to the surface area of ​​the main body is ≥0.05 (to ensure that the cooling gas flow efficiency is not significantly affected). The flared part is fixed to the noise-reducing outer shell 51 by adhesive bonding, which not only positions the noise-reducing inner shell 52, but also guides the airflow smoothly into the axial hole of the noise-reducing outer shell 51. A gap is reserved between the noise-reducing inner shell 52 and the noise-reducing outer shell 51. This gap can further buffer the airflow. At the same time, the frame structure of the noise-reducing inner shell 52 can disrupt the turbulence of the airflow and reduce the high-frequency noise caused by turbulence.

[0037] Working principle Cooling gas input: After the external cooling gas supply device is started, the cooling gas (usually room temperature compressed air, which does not require additional cooling treatment and reduces energy consumption) enters the connection hole on the heat dissipation shell 3 through the hose connection structure, and then flows into the input channel 411 of the directional cooling unit 4; the input channel 411 guides the cooling gas to the annular channel 410. Because the annular channel 410 is concentric with the annular shell 40 and the channel cross-section is uniform, the cooling gas can achieve a balanced pressure distribution in the annular channel 410, avoiding insufficient gas flow in the local nozzle 42 due to pressure difference. Directional jet cooling: The cooling gas in the annular flow channel 410 is distributed to each nozzle 42 through several output flow channels 412. The nozzle 42 sprays the cooling gas in a directional manner to the core heat-generating area of ​​the bearing 2 (the contact point between the rolling element and the inner and outer rings). The cooling gas is in direct contact with the surface of the bearing 2 and quickly absorbs the heat generated by friction during the operation of the bearing 2 through convection heat transfer, so that the temperature of the bearing 2 is maintained within a reasonable operating range (avoiding the decrease in the hardness of the bearing 2 material or the failure of lubrication due to overheating). Gas circulation: After absorbing heat, the cooling gas (hot gas) decreases in density and diffuses along the gap between the inner and outer rings of the bearing 2 to the outside of the heat dissipation housing 3 and the housing space 30. At the same time, some hot gas is discharged to the outside through the gap between the end cap 31 and the main shaft 1. At this time, the through hole 32 on the surface of the heat dissipation housing 3 plays a "two-way circulation" role: on the one hand, the hot gas in the housing space 30 is discharged to the outside through the through hole 32, avoiding the accumulation of hot gas in the housing space 30 and the resulting decrease in heat dissipation efficiency; on the other hand, ambient temperature air is naturally drawn into the housing space 30 through the through hole 32, forming a continuous "input-cooling-exhaust-replenishment" cycle. No additional power is needed to drive the gas circulation, simplifying the structure and reducing energy consumption. Noise control: During the process of cooling gas being injected through nozzle 42, the noise reduction component 5 at the output end of nozzle 42 works simultaneously: the open polyurethane foam of the noise reduction shell 51 absorbs the vibration noise generated during airflow injection through its own damping characteristics; at the same time, after the cooling gas enters the noise reduction inner shell 52, it is diverted through the uniform opening 53 of the main body to avoid the direct impact of airflow to generate turbulence, and the gap between the noise reduction inner shell 52 and the noise reduction outer shell 51 further buffers the airflow speed and reduces the generation of high-frequency noise; the flared part guides the airflow smoothly into the noise reduction shell 51 to avoid the formation of vortex noise at the outlet of nozzle 42, and finally achieves the synergy of "cooling" and "noise reduction".

[0038] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A heat dissipation structure for a machine tool spindle, comprising: The spindle body (1) has one end connected to the machine tool's drive system and the other end used to mount the tool holder. The bearings (2) are multiple and distributed at both ends of the main shaft (1) to support the weight of the main shaft (1) and the machining load; Its characteristic is that it further includes: A heat dissipation housing (3) is provided inside the heat dissipation housing (3) for accommodating the spindle, and end caps (31) are provided at both ends of the heat dissipation housing (3). A directional cooling unit (4) is provided on the inner side of the bearing (2) to uniformly spray cooling gas onto the surface of the bearing (2); The inner ring of the bearing (2) is fixed to the main shaft body (1), and the outer ring is fixed to the heat dissipation shell (3). There are gaps between the shell end cap (31) and the main shaft body (1), and between the inner and outer rings of the bearing (2) for cooling gas to flow.

2. The heat dissipation structure for a machine tool spindle according to claim 1, characterized in that, Also includes: Through holes (32), a plurality of which are evenly distributed on the surface of the heat dissipation shell (3), the through holes (32) are connected to the receiving space (30) to realize natural air intake and exhaust.

3. The heat dissipation structure for a machine tool spindle according to claim 2, characterized in that, The directional cooling unit (4) further includes: An annular housing (40) is positioned inside the bearing (2) by a heat dissipation shell (3). The annular housing (40) is formed by combining a first housing (401) and a second housing (402). Cooling gas flow channel (41) is disposed in an annular shell (40); Nozzle (42), the nozzle (42) having a plurality of nozzles evenly spaced along the circumference of the annular housing (40) on the surface of the annular housing (40) facing the bearing (2); The nozzle (42) is connected to the cooling gas channel (41) at its input end, and the cooling gas channel (41) is used to deliver external cooling gas to the nozzle (42).

4. The heat dissipation structure for a machine tool spindle according to claim 3, characterized in that, Also includes: Noise reduction component (5) is provided at the output end of nozzle (42) to reduce airflow noise.

5. The heat dissipation structure for a machine tool spindle according to claim 4, characterized in that, The noise reduction device (5) also includes: Mounting groove (50) is provided at the output end of nozzle (42). The mounting groove (50) extends along the axial direction of nozzle (42) from the output end of nozzle (42) to the input end of nozzle (42). A noise-reducing housing (51) is disposed in a mounting groove (50), the noise-reducing housing (51) is made of damping material and has an axial hole for cooling gas to pass through; The noise-reducing inner shell (52) is in the form of a frame with multiple openings (53). The noise-reducing inner shell (52) is disposed in the noise-reducing outer shell (51) and also has axial holes for cooling gas to pass through.

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