A milling head for a milling machine

Abstract

This application relates to a milling head for a milling machine tool, specifically within the technical field of milling heads. The milling head includes a housing, a vertical drive assembly rotatably mounted within the housing, and a horizontal drive assembly rotatably mounted within the housing. The vertical drive assembly is connected to the milling machine tool and drives the horizontal drive assembly to rotate. A milling cutter head is detachably mounted on the horizontal drive assembly. The milling head housing contains both a vertical and a horizontal cooling chamber. A coolant channel is provided on the inner side between the vertical and horizontal cooling chambers, and a coolant circulation pipe is provided on the outer side of both chambers. A vertical coolant propulsion assembly is mounted on the vertical drive assembly, and a horizontal coolant propulsion assembly is mounted on the horizontal drive assembly. This application solves the problems of delayed cooling, localized overheating, and complex structure in traditional milling heads, achieving beneficial effects such as reducing spindle temperature rise, suppressing thermal deformation, and improving machining accuracy and stability.

Description

Technical Field

[0001] This application relates to the field of milling head technology, and in particular to a milling head for a milling machine tool. Background Technology

[0002] Milling machine tools are core equipment in modern manufacturing for achieving high-precision and high-efficiency metal cutting. Their core actuator—the milling head—typically consists of a housing, spindle drive mechanism, tool mounting interface, and cooling and lubrication system. Currently, most mainstream milling heads use an external independent cooling pump with circulating coolant through pipelines, or rely on the machine tool's cooling system to supply coolant to the milling head housing jacket or tool holder channel via external hoses. Some high-end milling heads integrate a spiral groove guide structure inside the spindle to assist in axial coolant delivery; however, this structure only acts in one direction of the spindle and requires additional sealing isolation and pressure sources. These types of milling heads generally physically separate the drive transmission system from the cooling system, with coolant flow dependent on external power, resulting in problems such as pipeline redundancy, response lag, numerous sealing points, and complex maintenance.

[0003] However, during long-term, high-load continuous machining, the aforementioned milling head lacks the ability to coordinate, actively, and compactly dissipate heat from both the vertical drive components (such as the worm gear-worm reducer) and the horizontal drive components (such as the orthogonal worm gear-worm pair). This results in significant temperature rise of key transmission components, accumulation of thermal deformation, and decreased meshing accuracy. Consequently, it leads to increased tool vibration, increased surface roughness, abnormal tool wear, and even sudden failure, severely affecting machining stability and equipment lifespan. Summary of the Invention

[0004] This application provides a milling head for a milling machine tool, which can solve the technical problems of overheating, accelerated tool wear, and decreased machining accuracy caused by the lack of an effective cooling system during long-term high-load machining of traditional milling heads.

[0005] This application provides a milling head for a milling machine tool, employing the following technical solution: A milling head for a milling machine tool includes a milling head housing, a vertical drive assembly rotatably mounted inside the milling head housing, a horizontal drive assembly rotatably mounted inside the milling head housing, the vertical drive assembly being connected to the milling machine tool, the vertical drive assembly driving the horizontal drive assembly to rotate, a milling cutter head detachably mounted on the horizontal drive assembly, a vertical cooling cavity and a horizontal cooling cavity being provided inside the milling head housing, a coolant channel being provided on the inner side between the vertical and horizontal cooling cavities, a coolant circulation pipe being provided on the outer side of the vertical and horizontal cooling cavities, a vertical coolant pushing assembly being mounted on the vertical drive assembly, and a horizontal coolant pushing assembly being mounted on the horizontal drive assembly.

[0006] Optionally, the vertical drive assembly includes a drive connector for connecting to the electric spindle of a milling machine tool. A vertical worm gear is mounted on the drive connector, and a vertical turbine is mounted on the vertical worm gear. The vertical worm gear is connected to the vertical cooling chamber via a sealed bearing.

[0007] Optionally, the lateral drive assembly includes a lateral worm gear with a lateral turbine mounted on it. The lateral turbine meshes with a vertical turbine, and the lateral worm gear is connected to the lateral cooling chamber via a sealed bearing.

[0008] Optionally, the vertical coolant pushing assembly includes a vertical spiral pusher plate fixed on a vertical worm gear, with a first counterweight ring fixed at both ends of the vertical spiral pusher plate; the horizontal coolant pushing assembly includes a horizontal spiral pusher plate, with a second counterweight ring fixed at both ends of the horizontal spiral pusher plate; the horizontal spiral pusher plate has a T-shaped cross-section, and the second counterweight ring and the outer edge of the horizontal spiral pusher plate are in contact with the inner wall of the horizontal cooling chamber;

[0009] Optionally, the first counterweight ring is equipped with multiple sector-shaped counterweights. An axial slider is provided on the lower side of each sector-shaped counterweight. An axial threaded rod is threaded onto the axial slider. An axial spring is provided on both sides of the axial slider. The axial spring is sleeved on the axial threaded rod. A sliding groove is provided on the first counterweight ring. The axial threaded rod passes through the sliding groove and is used to adjust the position of the sector-shaped counterweights. One end of the axial spring abuts against the axial slider, and the other end abuts against the sliding groove.

[0010] Optionally, a guide groove is provided on the inner wall of the transverse cooling chamber, the guide groove extending to the side of the sealed bearing near the milling cutter head, the guide groove being used to allow the coolant to flow back.

[0011] Optionally, a heat dissipation grid is installed in the vertical cooling chamber. The heat dissipation grid includes a pair of flanges fixed in the vertical cooling chamber. A support ring is installed on the flange. A positioning strip is fixed on the outside of the support ring. A limit groove is opened on the flange. The positioning strip is engaged with the limit groove. The sealed bearing is engaged with the inner wall of the support ring.

[0012] Optionally, the milling head housing is provided with a vertical cutting fluid chamber and a horizontal cutting fluid chamber. A cutting fluid inlet pipe is fixed at the upper end of the vertical cutting fluid chamber, and a cutting fluid spray pipe is fixed at the end of the horizontal cutting fluid chamber near the milling cutter head.

[0013] Optionally, a coolant drain pipe is installed on the lower side of the milling head housing, and a coolant inlet pipe is installed on the upper end of the milling head housing.

[0014] Optionally, one end of the coolant circulation pipe is connected to the upper end of the vertical cooling chamber, and the other end is connected to the end of the horizontal cooling chamber near the milling cutter head.

[0015] In summary, this application includes at least one of the following beneficial technical effects:

[0016] This application provides a milling head for a milling machine tool. A vertical drive assembly and a horizontal drive assembly are integrated within the milling head housing, and a vertical coolant propulsion assembly and a horizontal coolant propulsion assembly are respectively mounted on them. The rotational motion of the drive assembly directly propels the coolant to actively circulate within the vertical cooling chamber, the horizontal cooling chamber, and the inner and outer cooling channels. Because the coolant propulsion assembly rotates synchronously with the drive shaft, efficient and low-power "motion-driven flow" cooling is achieved without an external pump. Furthermore, the vertical and horizontal cooling chambers are connected via a dual-path system: an inner coolant channel and an outer coolant circulation pipe. The interconnected design, along with the high-temperature priority flow direction of the coolant circulation pipe ("vertical cavity upper end → transverse cavity cutter head side"), significantly improves the coverage and response speed of key heat sources such as the worm gear meshing area, sealed bearings, and tool mounting end. The T-shaped cross-section of the transverse helical pusher plate, combined with the guide grooves and heat dissipation grilles, further enhances flow sealing and heat exchange efficiency. This solves the problems of traditional milling heads, such as delayed cooling, localized overheating, and complex structure, achieving the beneficial effects of reducing spindle temperature rise, suppressing thermal deformation, extending the life of transmission pairs, and improving machining accuracy and stability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application;

[0018] Figure 2 This is a cross-sectional structural diagram of an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of the vertical drive component and the horizontal drive component in an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the milling head housing structure according to an embodiment of this application;

[0021] Figure 5 This is a schematic diagram of the cross-sectional structure of the milling head housing according to an embodiment of this application;

[0022] Figure 6 This is a schematic diagram of the first balancing counterweight ring structure in an embodiment of this application;

[0023] Figure 7 This is a schematic diagram of the first balancing weight ring structure in an embodiment of this application.

[0024] In the diagram, 1. Milling head housing; 11. Vertical coolant chamber; 12. Horizontal coolant chamber; 13. Coolant inlet pipe; 14. Coolant spray pipe; 15. Coolant outlet pipe; 16. Coolant inlet pipe; 2. Vertical drive assembly; 21. Drive connector; 22. Vertical worm gear; 23. Vertical turbine; 24. Vertical helical push plate; 25. First counterweight ring; 251. Fan-shaped counterweight; 252. Axial slider; 253. Axial threaded rod; 254. Axial spring; 255. Sliding... 3. Shifting groove; 31. Lateral drive assembly; 32. Lateral worm gear; 4. Horizontal turbine; 5. Milling cutter head; 6. Vertical cooling chamber; 51. Sealed bearing; 52. Heat dissipation grille; 53. Flange; 54. Support ring; 55. Positioning strip; 56. Limiting groove; 7. Lateral cooling chamber; 61. Guide groove; 7. Coolant channel; 8. Coolant circulation pipe; 9. Vertical coolant propulsion assembly; 10. Lateral coolant propulsion assembly; 101. Horizontal spiral pusher plate; 102. Second balance weight ring. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1 -Appendix Figure 7 This application will be described in further detail below.

[0026] Reference Figure 1 , Figure 2 A milling head for a milling machine tool includes a milling head housing 1, a vertical drive assembly 2 rotatably mounted inside the milling head housing 1, a horizontal drive assembly 3 rotatably mounted inside the milling head housing 1, the vertical drive assembly 2 being connected to the milling machine tool, the vertical drive assembly 2 driving the horizontal drive assembly 3 to rotate, a milling cutter head 4 being detachably mounted on the horizontal drive assembly 3, a vertical cooling cavity 5 being provided inside the milling head housing 1, a horizontal cooling cavity 6 being provided inside the milling head housing 1, a coolant channel 7 being provided on the inner side between the vertical cooling cavity 5 and the horizontal cooling cavity 6, a coolant circulation pipe 8 being provided on the outer side of the vertical cooling cavity 5 and the horizontal cooling cavity 6, a vertical coolant pushing assembly 9 being mounted on the vertical drive assembly 2, and a horizontal coolant pushing assembly 10 being mounted on the horizontal drive assembly 3.

[0027] This embodiment provides an integrated dual-axis drive and self-driven synergistic cooling milling head structure. Its core lies in the deep coupling of the power transmission path and the thermal management path: the vertical drive component receives power input from the machine tool's electric spindle and simultaneously drives the transverse drive component to achieve tool spatial attitude adjustment; simultaneously, rotational motion is directly converted into coolant delivery kinetic energy, enabling the cooling system to form an active circulation without an independent pump source; the vertical and transverse cooling chambers correspond to the heat source distribution characteristics of the main drive shaft system and the end-cutting shaft system, respectively. They are both independently partitioned and connected via an inner coolant channel 7 and an outer coolant circulation pipe 8, forming a dual-path connection structure that balances response speed and flow stability; the detachable milling head 4 adopts a standard interface such as HSK-A63, BT40, or CAT40 taper shank structure, supporting quick tool changes and compatibility with multiple tool types; the entire system is encapsulated within a rigid milling head housing 1, the housing material of which can be a high-strength aluminum alloy such as 7075-T6 or ductile iron QT600-3, balancing lightweight design and thermal inertia buffering.

[0028] The milling head housing 1 is a closed shell that is integrally cast or precision assembled after separate machining. Internally, it has coaxial / orthogonal bearing housings for mounting the vertical drive assembly 2 and the transverse drive assembly 3. The inner wall of these housings is honed to ensure that the roundness and roughness Ra of the mounting surface of the sealed bearing 51 are ≤0.8 μm. The vertical drive assembly 2 is a power input unit that rotates around the Z-axis vertical direction of the machine tool. Its input end is rigidly connected to the output flange of the milling machine tool's electric spindle via a drive connector 21. The connection method includes keyway + end face gear meshing or interference fit + radial locking screws to ensure slip-free torque transmission and reliable axial positioning. The transverse drive assembly 3 is an output unit that rotates around the X-axis or Y-axis horizontal direction. Its axis is orthogonally arranged at 90° to the axis of the vertical drive assembly 2. The two are connected via a worm gear pair to achieve a high reduction ratio, high rigidity, and self-locking power transmission. The milling cutter head 4 is detachably fixed to the output end of the transverse drive assembly 3 using a triple positioning method of pull studs + conical surface + end face. The interface is compatible with ISO 7388-1 or DIN. The 69871 standard can also be replaced with a quick-change modular tool holder such as the Capto C4 interface; the vertical cooling cavity 5 extends axially along the vertical drive assembly 2, enveloping the vertical worm 22 in an annular or spiral groove shape, with a volume ratio of 18%–25% of the total internal cavity volume of the milling head housing 1. The cavity surface can be added with micro-textures such as a pit array formed by laser texturing, with a diameter of 50–100 μm and a depth of 10–20 μm to enhance liquid film adhesion and heat transfer coefficient; the transverse cooling cavity 6 extends axially along the transverse drive assembly 3, surrounding the transverse worm 31 and transverse turbine 32, with a flat elliptical cross-section to adapt to transverse space constraints, and the inner wall maintains a dynamic gap of 0.1–0.3 mm with the outer edge of the transverse spiral push plate 101; the coolant channel 7 is a radial channel or oblique flow channel that penetrates the inner wall of the vertical cooling cavity 5 and the transverse cooling cavity 6, with a diameter of Φ2–Φ5. The coolant circulation pipe 8 is an external flexible metal hose, such as a 316L stainless steel corrugated pipe or a hard alloy pipe. Its two ends are connected to the upper end of the vertical cooling chamber 5 and the end of the horizontal cooling chamber 6 near the milling head 4 through quick-connect couplings. The inner diameter of the pipe is Φ6–Φ10 mm, and the total length is controlled within 300–600 mm to reduce friction loss. The vertical coolant propulsion assembly 9 is fixed on the body of the vertical worm 22 and rotates synchronously with it to generate axial thrust to drive the coolant to flow upward or downward in one direction. The horizontal coolant propulsion assembly 10 is fixed on the body of the horizontal worm 31 and rotates synchronously with it to generate a combined effect of circumferential shearing and axial compression, which strengthens the liquid flow disturbance and boundary layer renewal in the horizontal cooling chamber 6.

[0029] The spatial arrangement of the vertical drive assembly 2 and the horizontal drive assembly 3 determines the overall kinematic characteristics of the machine: their rotation axes are strictly orthogonal and intersect near the theoretical cutting point of the milling cutter head 4, with an error ≤0.05 mm, thus ensuring the uniformity of dynamic decoupling and thermal deformation compensation benchmarks; the vertical cooling chamber 5 and the horizontal cooling chamber 6 are not simply connected in series, but achieve pressure coupling through the coolant channel 7 to achieve short-path flow guidance from the high-pressure zone to the low-pressure zone, and achieve steady-state high-flow circulation through the coolant circulation pipe 8, with the two working together to avoid local dry burning and air resistance; both the vertical coolant propulsion assembly 9 and the horizontal coolant propulsion assembly 10 are driven by the self-powered rotating body, without introducing additional energy consumption, and their pumping capacity is approximately quadratically related to the rotational speed Q ∝ n², maintaining a coolant flow rate of 0.3–2.5 rpm within the typical machining speed range of 500–6000 rpm. m / s, meeting the targeted cooling requirements of bearings, gear meshing areas and tool clamping sections; the detachability of the milling head 4 is not only reflected in the convenience of mechanical connection, but also in its thermal interface design - a thermally conductive silicone grease layer or copper foil gasket with a thickness of 0.05–0.1 mm is set between the tool holder and the output end of the transverse drive component 3 to ensure that cutting heat energy is efficiently introduced into the transverse cooling chamber 6 for dissipation.

[0030] Through the above technical solution, this application achieves the following: During the operation of the milling machine tool, when the vertical drive assembly 2 is driven to rotate by the electric spindle, on the one hand, the power is transmitted to the horizontal drive assembly 3 through the meshing of the vertical turbine 23 and the horizontal turbine 32, driving the milling cutter head 4 to complete the horizontal feed cutting; on the other hand, the vertical coolant push assembly 9 rotates synchronously with the vertical worm 22, forming an axial pressure gradient in the vertical cooling chamber 5, pushing the coolant into the horizontal cooling chamber 6 through the inner coolant channel 7, while some coolant is replenished by the outer coolant circulation pipe 8; the coolant entering the horizontal cooling chamber 6 is accelerated and circulated under the action of the horizontal coolant push assembly 10 and washes the surface of the horizontal worm 31, the horizontal turbine 32 and the clamping section of the milling cutter head 4. After absorbing heat, the high-temperature coolant flows back to the area near the sealed bearing 51 along the guide groove 61, and then returns to the vertical cooling chamber 5 through the coolant channel 7 or the circulation pipe 8 for secondary heat dissipation. Because the vertical cooling chamber 5 has a large heat capacity and surface area, and incorporates a heat dissipation grille 52, it can effectively buffer transient thermal loads; while the transverse cooling chamber 6 is close to the core area of ​​the heat source, achieving rapid thermal response. Therefore, this structure fundamentally solves the technical problems of high spindle system temperature rise, large thermal drift, and short tool life caused by passive cooling and path interruption in traditional milling heads, significantly improving machining accuracy retention, system operational stability, and multi-task adaptability under high-speed milling conditions.

[0031] Reference Figure 2 , Figure 3The vertical drive assembly 2 includes a drive connector 21, which is used to connect to the electric spindle of the milling machine tool. A vertical worm gear 22 is mounted on the drive connector 21, and a vertical turbine 23 is mounted on the vertical worm gear 22. The vertical worm gear 22 is connected to the vertical cooling chamber 5 through a sealed bearing 51.

[0032] The vertical drive assembly 2 is the core transmission unit that realizes the input of main force and the transmission of vertical motion. Its overall structure is designed with high rigidity, low vibration, and dynamic sealing as the goals. The drive connector 21 is a hollow cylindrical flange structure with a keyway and radial positioning stop on the outer periphery that matches the output end of the electric spindle. The inner hole has a threaded or tapered mating section for rigid connection with the output shaft of the electric spindle. Its material can be selected as 40CrNiMoA quenched and tempered steel, with surface nitriding treatment to improve wear resistance and torsional stiffness. This connector not only undertakes the torque transmission function, but also serves as the mounting base and axial positioning reference for the vertical worm gear 22.

[0033] The vertical worm 22 is a single- or double-start involute worm with a module of 2.5–4 mm and a helix angle of 15°–25°. The tooth surface is carburized, quenched, and ground to achieve a surface hardness of HRC58–62. One end is axially fixed to the inner extension shaft of the drive connector 21 by an interference fit or a lock nut, while the other end extends into the vertical cooling cavity 5 and is rotated and isolated from the cavity by a sealed bearing 51. The vertical worm 23 is a full-circle worm made of cast tin bronze ZCuSn10P1. Its tooth width matches the length of the worm meshing section, and its tooth profile is a modified Archimedean worm gear tooth profile conjugate with the worm. It is mounted on the input shaft of the transverse drive assembly 3 (see Specific Embodiment 3) and achieves torque output through key connection. It and the vertical worm 22 form a worm-worm gear transmission pair with a reduction ratio of 15:1 to 30:1. It has self-locking capability and can prevent the transverse drive assembly 3 from unexpectedly rotating due to gravity or cutting reaction force in the event of power failure or sudden shutdown.

[0034] The sealed bearing 51 is a double-row angular contact ball bearing or a deep groove ball bearing with a double-lip seal structure. The inner ring is interference-fitted with the journal of the vertical worm 22, and the outer ring is transition-fitted with the bearing housing bore of the vertical cooling chamber 5. Its sealing lip faces the inside of the cooling chamber and is made of fluororubber FKM material, which is resistant to coolant immersion and short-term temperature rise of 120°C. This bearing simultaneously bears the triple functions of radial load, axial thrust and dynamic sealing, ensuring that the coolant does not seep into the drive connector 21 side axially when the vertical worm 22 is rotating at a rated speed of ≤3000 r / min at high speed, and also preventing external oil mist or cutting debris from entering the vertical cooling chamber 5.

[0035] The aforementioned components work synergistically: the drive connector 21 stably guides the power output from the electric spindle into the vertical worm gear 22; the vertical worm gear 22 meshes with the vertical turbine 23, converting high-speed, low-torque input into low-speed, high-torque output to drive the subsequent lateral transmission chain; the sealed bearing 51 ensures reliable rotation of the vertical worm gear 22 while forming a physical isolation barrier between the cooling chamber and the external drive area. Together, these three components constitute an integrated vertical drive subsystem that integrates power input, mechanical transmission, and thermal management boundary control.

[0036] Through the above technical solution, this application achieves the following: when the electric spindle of the milling machine tool starts and outputs rotational power, the power is transmitted to the vertical worm 22 via the drive connector 21, which drives the vertical turbine 23 to rotate synchronously, thereby driving the transverse drive assembly 3 to move. During this process, the sealed bearing 51 continuously maintains the sealed state of the vertical cooling chamber 5, preventing the coolant from migrating axially along the vertical worm 22 to the interface between the drive connector 21 and the electric spindle. This prevents the coolant from contaminating the electric spindle lubrication system and also prevents external impurities from invading the cooling chamber in the reverse direction, thus reducing the heat dissipation efficiency. At the same time, the self-locking characteristic of the worm-turbine mechanism improves the operational safety of the system under emergency stop, power failure, or heavy-load cutting. This structure solves the technical problems commonly found in the background technology, such as unreliable dynamic sealing between the vertical drive component and the cooling chamber, insufficient transmission stability, and the easy occurrence of uncontrolled displacement of the transverse assembly in the shutdown state. It significantly improves the reliability and lifespan of the milling head under multi-axis linkage and high-precision continuous cutting conditions.

[0037] Reference Figure 2 , Figure 3 The lateral drive assembly 3 includes a lateral worm gear 31, on which a lateral turbine 32 is mounted. The lateral turbine 32 meshes with the vertical turbine 23. The lateral worm gear 31 is connected to the lateral cooling chamber 6 via a sealed bearing 51.

[0038] The transverse drive assembly 3, as the core transmission unit for converting the vertical main driving force to transverse cutting output in the milling direction, must have its structural design taking into account power transmission efficiency, axial space constraints, rotary seal reliability, and thermal management adaptability. This assembly uses the transverse worm 31 as the main rotating shaft, bearing the radial load and torque output of the milling cutter head 4; the transverse turbine 32 is rigidly connected to the transverse worm 31, forming an integrated turbine-worm pair. It receives the rotational motion from the vertical turbine 23 through tooth surface meshing and converts the torque into the rotation of the transverse worm 31, thereby driving the milling cutter head 4 to perform transverse feed or yaw cutting operations. The transverse worm 31 is supported at both ends on the inner wall of the milling head housing 1, with one end penetrating into the transverse cooling chamber 6. Rotational support and isolation from the chamber are achieved through a sealed bearing 51. The sealed bearing 51 is a composite radial sealing bearing with a double-lip structure fluororubber seal ring and a stainless steel skeleton. The inner ring is interference-fitted to the journal of the transverse worm 31, and the outer ring is press-fitted into the bearing seat hole of the corresponding end cover of the transverse cooling chamber 6. This ensures that the coolant does not leak axially into the transmission mechanism, while allowing the transverse worm 31 to rotate stably at a rated speed of ≤1200 r / min. The meshing relationship between the transverse turbine 32 and the vertical turbine 23 is a worm gear meshing with a vertical axis angle of 90°, a module of 2.5 mm, a pressure angle of 20°, a worm thread count of 1, and a turbine tooth count of 40. This parameter combination ensures a transmission ratio of i=40:1 while suppressing the risk of reverse self-locking and reducing meshing slip speed to reduce heat generation. The transverse turbine 32 can be made of tin bronze ZCuSn10P1 integral casting followed by precision machining of the tooth profile, or it can be replaced with a 20CrMnTi alloy steel gear ring heat-fitted structure with surface nitriding treatment to improve wear resistance and anti-galling ability. The transverse worm 31 can be made of 40Cr quenched and tempered with surface high-frequency quenching to a hardness of HRC52–56, or it can be replaced with a ceramic matrix composite material such as Si3N4 reinforced Al2O3 hollow shaft structure, which reduces weight by 35% under the same stiffness, reduces rotational inertia, and improves dynamic response characteristics.

[0039] The transverse worm gear 31 serves as the rotation reference axis of the transverse drive assembly 3. Its axis is parallel and coplanar with the rotation axis of the milling cutter head 4, and is used to directly or indirectly transmit cutting torque. The transverse turbine 32 serves as the force-bearing component at the power input end. Its rim is provided with an annular oil groove and radial oil guide holes. During the meshing process with the vertical turbine 23, the lubricating oil is centrifugally thrown into the meshing area through the oil guide holes to form a continuous oil film. The meshing position of the transverse turbine 32 and the vertical turbine 23 is located in the area where their axes intersect, ensuring the shortest force flow path and the highest contact stiffness. In addition to bearing the radial load, the sealed bearing 51 also adjusts and compensates for the axial displacement caused by thermal expansion through a preload structure such as spring preload or shims, maintaining the long-term sealing integrity of the transverse cooling chamber 6. The transverse worm gear 31 and the transverse cooling chamber 6 are mechanically connected by a sealed bearing 51. This connection serves three functions: first, it is a path for transmitting rotational motion; second, it is a static isolation barrier for the cooling medium; and third, it is a vibration transmission blocking interface. When the transverse worm gear 31 experiences slight axial movement due to cutting impact, the elastic sealing lip of the sealed bearing 51 undergoes controllable deformation, absorbing the displacement without damaging the seal, thus preventing coolant from leaking axially into the gear meshing area and causing lubrication failure.

[0040] The synergistic effect of the components is as follows: When the vertical turbine 23 rotates continuously, its tooth surface pushes the tooth groove of the transverse turbine 32, causing the transverse turbine 32 to drive the transverse worm 31 to rotate synchronously; the transverse worm 31 rotates stably around its own axis under the constraint of the sealed bearing 51, and the milling cutter 4 connected to its output end obtains transverse cutting motion; at the same time, the coolant in the transverse cooling chamber 6 flows circumferentially along the inner wall of the chamber under the drive of the transverse spiral pusher 101, and the sealed bearing 51 is located at the key section of the coolant flow channel—its outer bearing seat integrates a guide slope, which guides part of the coolant to the bearing friction pair end face, achieving dual cooling and lubrication of the sealing lip and rolling elements, significantly extending the seal life. The connection between the transverse worm 31 and the transverse cooling chamber 6 is no longer just a static support relationship, but forms a functional integrated node of "rotating shaft—sealing interface—cooling flow channel".

[0041] Through the above technical solution, the following is achieved: While maintaining the vertical main driving force source unchanged, the vertical rotational motion is efficiently converted into horizontal rotational output through the orthogonal meshing of the horizontal worm 31, horizontal turbine 32, and vertical turbine 23. The sealed bearing 51 simultaneously undertakes the triple tasks of rotational support, cooling chamber isolation, and local flow field guidance, ensuring that the horizontal drive assembly 3 maintains transmission accuracy and cooling system reliability under high-load cutting conditions. Because the horizontal turbine 32 and vertical turbine 23 mesh directly, intermediate couplings or transition gear sets are eliminated, reducing the transmission chain length and cumulative error. This solves the technical problems of complex horizontal output shaft structure, redundant axial dimensions, and easy intrusion of cooling medium into the transmission pair in traditional multi-axis milling heads. Furthermore, because the horizontal worm 31 is directly connected to the horizontal cooling chamber 6 through the sealed bearing 51, the need for additional independent cooling pipe penetration structures is avoided, eliminating the risk of leakage and local heat accumulation, thereby improving the overall environmental adaptability and long-term operational stability of the milling head.

[0042] Reference Figure 2 , Figure 3 The vertical coolant pushing assembly 9 includes a vertical spiral pusher plate 24 fixed on the vertical worm gear 22. The vertical spiral pusher plate 24 has a first counterweight ring 25 fixed at both ends. The horizontal coolant pushing assembly 10 includes a horizontal spiral pusher plate 101. The horizontal spiral pusher plate 101 has a second counterweight ring 102 fixed at both ends. The horizontal spiral pusher plate 101 has a T-shaped cross-section. The second counterweight ring 102 and the outer edge of the horizontal spiral pusher plate 101 are in contact with the inner wall of the horizontal cooling chamber 6.

[0043] This embodiment proposes an integrated coolant propulsion structure that directly drives coolant circulation based on the rotational motion of a drive shaft. Its core lies in rigidly fixing a spiral pusher plate to a rotary drive component, utilizing the rotational kinetic energy of the shaft system itself to convert into directional axial delivery force for the coolant. Dynamic balance under high-speed conditions is achieved through a counterweight ring, while an effective sealed flow channel is formed by the tight fit between the T-shaped cross-section and the cavity wall. This allows for coordinated circulation of coolant between the vertical and horizontal cooling chambers without relying on an external pumping device. This solution eliminates the need for complex cooling drive systems that require additional motors, piping valves, and independent sealed cavities, significantly reducing overall size, assembly difficulty, and the number of potential failure points.

[0044] The vertical spiral pusher 24 is a thin-walled metal plate structure extending in a spiral line along the axial direction of the vertical worm 22. Its helix angle is 12° to 20°, optionally 15°. It is made of high-strength aluminum alloy such as 7075-T6 or stainless steel such as SUS304. It is circumferentially fixed to the outer cylindrical surface of the vertical worm 22 by interference fit or radial screw fastening to ensure that no relative slippage occurs when transmitting torque. Its function is to continuously push the coolant in the vertical cooling cavity 5 axially upward or downward when the vertical worm 22 rotates, forming a unidirectional pulsating propulsion flow field. As an optional embodiment, the vertical spiral pusher 24 can also adopt a double-headed spiral structure, that is, two sets of spiral blades are arranged on the same worm in opposite directions to offset part of the axial thrust; or it can be replaced with a variable pitch spiral structure with a gradually changing pitch to adapt to the dynamic requirements of coolant flow rate at different axial positions in the cavity.

[0045] The first counterweight ring 25 is a ring-shaped component with a segmented layout, consisting of multiple fan-shaped counterweight blocks 251 evenly distributed along the circumference. Each fan-shaped counterweight block 251 is slidably connected to the end flange of the vertical spiral push plate 24 via radial grooves and is fixed by locking screws. After initial design, its mass distribution allows for dynamic balance calibration after assembly by fine-tuning the radial position of each fan-shaped counterweight block 251, with calibration accuracy reaching G2.5 level ISO 1940-1 standard. The material is high-density alloy steel such as 40CrNiMoA or tungsten alloy to provide sufficient inertia compensation within a limited space. As an optional implementation, the first counterweight ring 25 can also adopt an integral ring-shaped counterweight structure with multiple sets of axial adjustment grooves on its outer circumference, allowing for fine-tuning of the mass by adding or removing embedded counterweight blocks; or it can be replaced with a magnetic adjustable counterweight module, utilizing the attraction force between the permanent magnet array and the magnetic base to achieve non-mechanical contact counterweight adjustment.

[0046] The transverse spiral pusher 101 is an axial spiral component mounted on the transverse worm 31. Its cross-section is T-shaped, and the flange of the T-shaped structure forms a surface contact with the inner wall of the transverse cooling cavity 6, with a contact gap ≤0.05 mm. This ensures that during the rotation of the transverse worm 31, the flange remains tightly against the cavity wall, forming a closed spiral conveying channel together with the inner wall of the cavity. The material is wear-resistant engineering plastic such as PEEK or surface-nitrided alloy steel such as 20CrMnTi, to balance low friction and structural strength. Alternatively, the T-shaped cross-section of the transverse spiral pusher 101 can be replaced with an inverted L-shaped or dovetail-shaped cross-section, as long as it ensures that the protrusion forms a continuous, stable, and low-leakage radial sealing band with the cavity wall. Its installation method can also be changed from integral heat-fitting to a split snap-fit ​​connection for easier disassembly and maintenance.

[0047] The second counterweight ring 102 is a ring-shaped counterweight structure symmetrically arranged at both ends of the transverse spiral pusher plate 101. Its inner hole transitions with the transverse worm gear 31, and its outer edge contour remains concentric with the inner wall of the transverse cooling cavity 6. Its maximum outer diameter is 0.1 to 0.3 mm smaller than the inner diameter of the cavity. Its function is to counteract the mass eccentricity and rotational centrifugal force imbalance caused by the T-shaped cross-section of the transverse spiral pusher plate 101, and to suppress the vibration amplification effect of the transverse drive assembly 3 at high speeds. The material is the same as or matches the first counterweight ring 25 to ensure that the coefficients of thermal expansion are similar. As an optional embodiment, the second counterweight ring 102 can also be integrated into the body of the transverse spiral pusher plate 101, that is, the annular counterweight section is directly thickened and extended at both ends of the T-shaped main plate to achieve structural integration; or a liquid dynamic balance cavity structure is adopted, in which a freely flowing inert liquid medium is encapsulated in the annular cavity, and the imbalance is compensated in real time by utilizing the automatic migration characteristics of the liquid center of gravity.

[0048] There is a defined mechanical coupling relationship between the above components: the rotational motion of the vertical worm 22 directly drives the vertical spiral pusher 24 to rotate synchronously, thereby pushing the coolant in the vertical cooling chamber 5 to flow axially; after the coolant enters the transverse cooling chamber 6 through the coolant channel 7, the transverse worm 31 drives the transverse spiral pusher 101 to rotate, and the closed spiral flow channel formed by the T-shaped flange and the cavity wall forces the coolant to the near end of the milling head 4 along the transverse worm 31 axially; the first balance weight ring 25 and the second balance weight ring 102 respectively constrain the center of mass of the vertical and transverse rotation systems, so that they maintain low amplitude stable operation within their respective speed ranges; the T-shaped structure of the transverse spiral pusher 101 not only provides fluid thrust, but the contact state between its flange and the cavity wall is also directly affected by the rotational accuracy and support stiffness of the transverse worm 31, thus together with the coaxiality of the sealed bearing 51 and the cylindricity of the inner hole of the transverse cooling chamber 6, it constitutes the key constraint condition for coolant delivery efficiency.

[0049] Through the above technical solution, this application achieves the following: when the vertical drive assembly 2 of the milling machine tool's electric spindle is running, the vertical worm 22 rotates, driving the vertical spiral pusher 24 to work, pushing the coolant upward from the bottom of the vertical cooling chamber 5; after the coolant flows into the transverse cooling chamber 6 through the inner coolant channel 7, the transverse worm 31 rotates synchronously under the meshing transmission of the vertical turbine 23 and the transverse turbine 32, driving the transverse spiral pusher 101 to make spiral conveying motion in the closed flow channel formed by the T-shaped cross section and the cavity wall, continuously pressing the coolant to one end close to the milling cutter head 4; during this process, the first balance weight ring 25 and the second balance weight ring 102 respectively implement dynamic balance compensation for the vertical and transverse rotation systems, suppressing high-frequency vibration caused by uneven mass distribution of the spiral pusher, and ensuring the stability and continuity of the coolant conveying flow field. Because the external coolant pump and its associated piping and control system have been eliminated, the problems of redundant structure, slow response, poor sealing reliability and high maintenance cost of the existing milling head cooling system have been solved. Therefore, the technical effects of highly integrated cooling drive, strong controllability of coolant flow field, high overall machine operation stability and significantly reduced system failure rate have been achieved.

[0050] Reference Figure 3 , Figure 6 , Figure 7 The first counterweight ring 25 is equipped with multiple sector-shaped counterweight blocks 251. An axial slider 252 is provided on the lower side of the sector-shaped counterweight block 251. An axial threaded rod 253 is threaded on the axial slider 252. An axial spring 254 is provided on both sides of the axial slider 252. The axial spring 254 is sleeved on the axial threaded rod 253. A sliding groove 255 is provided on the first counterweight ring 25. The axial threaded rod 253 passes through the sliding groove 255 and is used to adjust the position of the sector-shaped counterweight block 251. One end of the axial spring 254 abuts against the axial slider 252 and the other end abuts against the sliding groove 255.

[0051] The first counterweight ring 25 is a non-continuous counterweight array. The first counterweight ring 25 has fan-shaped counterweights 251 evenly distributed along the circumference, and each group is composed of radially adjustable sliders.

[0052] The "discontinuous counterweight array" refers to the first balancing counterweight ring 25 not adopting an integral ring structure, but rather composed of multiple independent counterweight units that are separate and unconnected to each other. Each unit is arranged at equal angular intervals along the circumference of the vertical spiral pusher plate 24, forming a discrete mass distribution pattern. This structure avoids the problem of traditional integral ring counterweights requiring overall replacement or machining repair due to local mass deviations leading to global imbalance, while also providing a physical basis for single-point mass adjustment. The array has 6 to 12 units, corresponding to a circumferential distribution angle of 30° to 60°, ensuring adjustment resolution while also considering structural rigidity and assembly space constraints. The radial cross-section of each fan-shaped counterweight 251 is fan-shaped, with the inner arc surface fitting against the mounting base surface at the end of the vertical spiral pusher plate 24, and the outer arc surface profile matching the curvature of the inner wall of the vertical cooling cavity 5 to maintain rotational inertial symmetry. The material used is high-density alloy steel, tungsten alloy, or sintered hard alloy, with a density range of 7.8 g / cm³ to 19.3 g / cm³. g / cm³, to adapt to centrifugal force loads under different speed conditions.

[0053] Among them, the "fan-shaped counterweight 251" is the basic functional unit that constitutes the discontinuous array. Its geometry is defined by the central angle, radial thickness and axial height. The central angle is 20° to 45°; the radial thickness is 8 mm to 25 mm; the axial height is consistent with the thickness of the flange at the end of the vertical spiral push plate 24, which is 12 mm to 30 mm. Each fan-shaped counterweight 251 slides with the corresponding guide rail on the end face of the vertical spiral push plate 24 through the sliding groove 255 on the back, and is axially limited by the axial spring 254 to ensure that no axial movement occurs during operation.

[0054] The phrase "each group consists of radially adjustable sliders" refers to the fact that each sector counterweight 251 integrates an independent radial displacement adjustment mechanism. This slider is an embedded structure, set along the radial centerline of the sector counterweight 251. The axial slider 252 is embedded in the sliding groove 255 of the sector counterweight 251. The axial slider 252 is provided with a fine-tuning threaded hole, which is threadedly connected to the axial threaded rod 253. Rotating the axial threaded rod 253 can drive the axial slider 252 to move slightly radially, thereby performing targeted mass compensation for the rotating subsystem consisting of the vertical spiral push plate 24 and the vertical worm gear 22 rigidly connected to it. This adjustment mechanism does not rely on disassembly or replacement of parts. It only requires that after the milling head is statically assembled, the amplitude and phase of the unbalance are obtained with the help of a dynamic balancing tester, and then the radial displacement command is distributed to each sector counterweight 251 according to the vector decomposition principle to complete the closed-loop calibration.

[0055] Through the above technical solution, this application achieves the following: without changing the original structural layout and transmission path of the vertical drive assembly 2, the first balance counterweight ring 25 is decoupled into independently adjustable discrete mass units, and each unit is given radial displacement capability with millimeter-level precision. Because the first balance counterweight ring 25 adopts a non-continuous counterweight block array, and each sector counterweight block 251 is composed of radially adjustable sliders, it can target and correct the local mass asymmetry generated when the vertical spiral push plate 24 rotates at high speed, overcoming the technical defects of traditional integral counterweight rings that cannot be locally adjusted and cannot meet the microgram-level dynamic balance precision requirements at high speeds. In turn, it effectively suppresses the peak vibration acceleration of the vertical drive assembly 2 under operating conditions above 3000 r / min, reduces the dynamic contact stress of the meshing pair between the sealed bearing 51 and the vertical turbine 23, delays the pressure pulsation during the coolant propulsion process, ensures the stability of the coolant flow field in the vertical cooling chamber 5, and ultimately improves the overall running stability and long-term machining reliability of the milling head.

[0056] (The structure and principle of the second counterweight ring 102 are the same as those of the first counterweight ring 25, and will not be described in detail here.)

[0057] Reference Figure 2 , Figure 5 A guide groove 61 is provided on the inner wall of the transverse cooling chamber 6. The guide groove 61 extends to the side of the sealed bearing 51 near the milling cutter head 4. The guide groove 61 is used to allow the coolant to flow back.

[0058] This embodiment achieves active diversion of coolant in the area adjacent to the sealed bearing by setting a directional extending guide groove 61 on the inner wall of the transverse cooling chamber 6. This significantly improves the problem of coolant stagnation and poor return in this local area, thereby ensuring the continuity of the coolant circulation path and pressure stability, and indirectly improving the lubrication conditions and thermal management reliability of the sealed bearing 51.

[0059] The transverse cooling cavity 6 is an annular or near-annular closed cavity arranged axially along the transverse drive assembly 3 inside the milling head housing 1. Its inner wall is a smooth curved surface that forms a dynamic seal with the outer edge of the transverse spiral push plate 101 and the second balance counterweight ring 102. The guide groove 61 is a groove structure formed by machining along the inner wall axially or spirally. Its cross-section is rectangular, trapezoidal or arc-shaped, with a depth of 0.3 mm to 1.2 mm and a width of 1.5 mm to 4.0 mm. Its length starts from the main section of the transverse cooling cavity 6 and extends continuously to the radial projection boundary of the mounting position of the sealed bearing 51. Its end is located in the axial end face projection area of ​​the outer ring of the sealed bearing 51 near the milling cutter head 4. This arrangement ensures that the guide groove 61 can effectively cover the low flow rate area where the coolant is easily pushed by the transverse spiral push plate 101 and accumulates on the front side of the bearing. As an optional implementation, the guide channel 61 can be a single axial straight channel, or two or more axial channels evenly distributed along the circumference, or a continuous spiral channel spiraling upward along the inner wall with a helix angle of 5° to 15°, to adapt to the liquid film distribution characteristics under different speed conditions; the surface of the channel is polished to a roughness Ra≤0.8 μm to reduce flow resistance.

[0060] Among them, the sealed bearing 51 is an angular contact ball bearing or a double-row cylindrical roller bearing. Its outer ring is interference-fitted into the bearing housing hole at the end of the transverse cooling cavity 6, and its inner ring is interference-fitted with the transverse worm 31. The end position of the guide groove 61 is strictly limited to the extended projection range of the axial end face of the outer ring of the sealed bearing 51 towards the milling cutter head 4. That is, the axial distance between the end of the guide groove 61 and the end face of the outer ring of the sealed bearing 51 on this side is not greater than 0.5 mm, thereby ensuring that the coolant is guided away from the high-pressure retention area before entering the bearing sealing lip. This positioning relationship does not depend on the bearing preload or assembly tolerance, but is only guaranteed by the one-time boring and milling process during the machining of the milling head housing 1, and has process robustness.

[0061] The phrase "used to facilitate coolant recirculation" does not refer to the independent formation of a complete circuit. Rather, it refers to the localized formation of a low-resistance reverse channel within the transverse cooling chamber 6. This allows the coolant, pushed circumferentially by the transverse spiral pusher 101 and climbing along the chamber wall, to settle due to the weakened centrifugal effect in front of the sealed bearing 51. Under the combined action of gravity and the slight pressure difference within the chamber, the coolant flows axially or spirally along the guide channel 61 towards the connection port of the coolant circulation pipe 8 or the low-level outlet of the transverse cooling chamber 6. This function does not change the main circulation direction of the coolant, i.e., from the vertical cooling chamber 5 → coolant channel 7 → transverse cooling chamber 6 → coolant circulation pipe 8, but is specifically used to eliminate local dead zones. As a variation, the end of the guide channel 61 can be connected to a pre-set collection pit at the bottom of the transverse cooling chamber 6, and then introduced into the coolant discharge pipe 15 branch through micro-holes with a diameter of Φ0.6 mm to Φ1.0 mm, forming an auxiliary recirculation sub-path.

[0062] The synergistic effect of each structure is manifested as follows: the rotation of the transverse spiral pusher 101 propels the coolant to move circumferentially along the transverse cooling chamber 6, and its outer edge adheres to the chamber wall to form a dynamic positive pressure zone; when the coolant travels to the vicinity of the sealed bearing 51, the flow velocity decreases and the static pressure increases due to structural abrupt changes and flow channel contraction, which easily forms eddies and liquid film accumulation; at this time, the guide channel 61, with its axial penetration and precise terminal positioning, provides a radial-axial composite pressure relief path for the high static pressure zone, so that some coolant preferentially flows along the channel to the downstream area of ​​the chamber with lower pressure, thereby breaking the local pressure balance, inhibiting bubble retention and liquid phase separation, and maintaining uniform coverage of coolant in the transverse cooling chamber 6 throughout the entire circumference.

[0063] Through the above technical solution, this application achieves the following: a guide channel 61 extending to the side of the sealed bearing 51 near the milling head 4 is provided on the inner wall of the transverse cooling chamber 6, so that the coolant pushed by the transverse spiral pusher 101 to the area adjacent to the sealed bearing can be promptly removed from the stagnation area by means of the low resistance channel provided by the guide channel 61 and flow back to the downstream of the cooling system; because the structural shape, size parameters and terminal space positioning of the guide channel 61 are all adapted to the natural accumulation law of the coolant in the transverse cooling chamber 6 in front of the sealed bearing 51, the problem of poor coolant return and local accumulation in this area is effectively alleviated, and the phenomena of insufficient lubrication, abnormal temperature rise and uneven cooling heat exchange of the sealed bearing 51 caused by this are avoided, thereby improving the thermal stability and operational reliability of the milling head under continuous high-load milling conditions.

[0064] Reference Figure 2 , Figure 3 , Figure 5 A heat dissipation grille 52 is installed inside the vertical cooling chamber 5. The heat dissipation grille 52 includes a pair of flanges 53 fixed inside the vertical cooling chamber 5. A support ring 54 is installed on the flange 53. A positioning strip 55 is fixed on the outside of the support ring 54. A limit groove 56 is opened on the flange 53. The positioning strip 55 is engaged with the limit groove 56. The sealed bearing 51 is engaged with the inner wall of the support ring 54.

[0065] This embodiment significantly enhances the heat exchange efficiency and flow stability of the coolant within the vertical cooling chamber 5 by integrating modular heat dissipation grilles 52 inside the chamber, without adding an external cooling power source. The flange 53, serving as the basic load-bearing structure, is rigidly fixed to the inner walls of both axial ends of the vertical cooling chamber 5 via interference fit or bolt fastening, ensuring the overall structure's vibration resistance and positional accuracy under high-speed rotation conditions. The support ring 54 is a hollow annular component with a rectangular or trapezoidal radial cross-section, and is made of a material with a thermal conductivity of not less than 150. Aluminum alloys such as 6061-T6 or copper alloys such as H62 brass with a strength of W / (m·K) serve both as coolant flow channel dividers and as efficient heat conduction paths, rapidly diffusing heat from the vertical drive assembly 2, via the sealed bearing 51, to the cavity laterally to the milling head housing 1. Positioning strips 55 are symmetrically distributed along the outer circumference of the support ring 54, numbering 3–6. Their cross-sections are convex or dovetail-shaped, forming a radial and axial double-constraint mechanical snap-fit ​​with the corresponding limiting grooves 56 on the flange 53. This snap-fit ​​structure allows the support ring 54 to be finely adjusted circumferentially along the plane of the flange 53 during assembly to accommodate the installation eccentricity of the sealed bearing 51, and also supports later replacement without disassembly. The limiting grooves 56 are either continuous straight grooves or segmented arc-shaped grooves, with a groove width tolerance controlled within ±0.05 mm and a depth of 1.2–2.0 mm. mm, ensuring no looseness or gap after the positioning strip 55 is inserted; the outer ring of the sealed bearing 51 and the inner wall of the support ring 54 adopt a transition fit H7 / k6, while the inner ring is interference-fitted with the vertical worm gear 22, so that the support ring 54 simultaneously constitutes the axial positioning reference and heat conduction interface of the bearing. This design breaks through the limitations of traditional methods that rely solely on natural heat exchange through the inner wall of the cavity, forcibly dividing the originally single-channel laminar coolant into multiple spiral turbulent flow paths, extending the effective heat exchange stroke, and increasing the turbulence intensity per unit volume of coolant.

[0066] The flange 53 can be replaced with an annular steel plate with a central through hole and welded to the end of the vertical cooling cavity 5, or an integrally cast structure can be used to omit the assembly process; the support ring 54 can also be formed by splicing two split rings, with a stop for positioning and screw locking on the splicing surface, which facilitates installation in narrow cavities; the snap-fit ​​connection between the positioning strip 55 and the limiting groove 56 can also be replaced with an elastic snap-fit ​​structure, such as a cantilevered plastic hook embedded in a metal groove, or a magnetic positioning structure with a neodymium iron boron permanent magnet embedded in the positioning strip 55, and a magnetic steel sheet at the bottom of the limiting groove 56, or by filling the limiting groove 56 with curable silicone to achieve flexible positioning and vibration reduction; the inner wall surface of the support ring 54 can be added with a spiral heat-conducting texture 0.1–0.3 mm deep, or sprayed with a coating thickness of 15–30 mm. The aluminum nitride ceramic coating with a diameter of μm further enhances the interfacial thermal conductivity density; the snap-fit ​​relationship between the sealed bearing 51 and the inner wall of the support ring 54 can also be achieved by setting an axial groove on the inner wall of the support ring 54 and embedding an elastic O-ring in the groove to achieve a pre-tightened flexible snap-fit, which takes into account both thermal expansion compensation and vibration isolation.

[0067] The synergistic effect of each component is manifested as follows: flange 53 provides a static installation reference; support ring 54, relying on its structural rigidity and high thermal conductivity, becomes the main channel for heat transfer; positioning strip 55 and limiting groove 56 jointly ensure the spatial attitude stability of support ring 54 under dynamic load; and the direct contact between sealed bearing 51 and support ring 54 opens up an efficient longitudinal heat conduction link of "vertical worm 22 → sealed bearing 51 → support ring 54 → flange 53 → milling head housing 1"; when the coolant flows through the annular gap channel formed by the support ring 54, the flow state changes from laminar to turbulent due to the disturbance of the edge of positioning strip 55 and the surface roughness of support ring 54, the Nusselt number Nu increases by 20%–35%, and the equivalent heat transfer area increases by more than 1.8 times.

[0068] Through the above technical solution, the following is achieved: an integrated heat dissipation grille 52 with structural support, enhanced heat conduction, and flow field regulation functions is constructed within the vertical cooling chamber 5; after the coolant enters the vertical cooling chamber 5, it is divided into multiple sub-channels that spiral along the circumference by the support ring 54, resulting in a more uniform flow velocity distribution and avoiding local stagnation and heat accumulation; because the support ring 54 is directly engaged with the sealed bearing 51, the frictional heat generated during the operation of the vertical drive assembly 2 is rapidly introduced into the support ring 54 through the outer ring of the bearing, and then radiated and dissipated to the milling head housing 1 through the flange 53, significantly reducing heat loss. Temperature rise in the meshing area of ​​the vertical worm gear 22 and the vertical turbine 23 is reduced; because the positioning strip 55 and the limiting groove 56 form a precision snap-fit ​​that can be repeatedly disassembled and reassembled, the heat dissipation grille 52 can be replaced or cleaned without disassembling the entire milling head housing 1, shortening the maintenance cycle by more than 40%; ultimately, without adding pumps or valves, changing the coolant formula, or increasing the circulation pressure, the average temperature drop of the vertical cooling chamber 5 reaches 8–12℃, effectively alleviating the problem of transmission error accumulation of the vertical drive component 2 caused by thermal deformation and improving the dimensional reproduction accuracy of milling.

[0069] Reference Figure 1 , Figure 2 , Figure 3 The milling head housing 1 is provided with a vertical cutting fluid chamber 11 and a horizontal cutting fluid chamber 12. A cutting fluid inlet pipe 13 is fixed at the upper end of the vertical cutting fluid chamber 11, and a cutting fluid spray pipe 14 is fixed at the end of the horizontal cutting fluid chamber 12 near the milling cutter head 4.

[0070] The milling head housing 1 is a rigid shell, integrally cast or machined in sections, made of high-strength aluminum alloy or ductile iron. Its interior is formed by precision boring and CNC milling, creating isolated yet functionally partitioned cavities. The vertical cutting fluid cavity 11 is arranged axially along the milling head housing 1, with a cylindrical or rectangular cross-section. Its axis coincides with the rotation center line of the vertical drive assembly 2, and it is used to receive and temporarily store externally supplied cutting fluid. The transverse cutting fluid cavity 12 extends horizontally along the milling head housing 1, its axis perpendicular to the axis of the vertical cutting fluid cavity 11 and parallel to the rotation center line of the transverse drive assembly 3. Its cross-section is elliptical or rectangular with rounded corners to accommodate the spatial layout of the transverse worm gear 31 and its surrounding support structure. The two cavities are connected by an unnumbered internal guide channel, which is part of the main structure of the milling head housing 1. This channel is located between the lower side wall of the vertical cutting fluid cavity 11 and the starting end of the transverse cutting fluid cavity 12, with an inner diameter of Φ6~Φ12 mm and a surface roughness Ra≤1.6. μm ensures low resistance and directional delivery of cutting fluid.

[0071] The cutting fluid inlet pipe 13 is a stainless steel rigid pipe or a reinforced polytetrafluoroethylene hose with an outer diameter of Φ8 to Φ15 mm. One end is fixed to the center of the top of the vertical cutting fluid chamber 11 via a threaded sealing joint such as NPT 1 / 4″ or G3 / 8″, and the other end is connected to the central cutting fluid supply system of the machine tool. The axis of the cutting fluid inlet pipe 13 is collinear with the axis of the vertical cutting fluid chamber 11. The inlet end is equipped with a one-way valve and a pressure buffer section to prevent backflow and pressure shock. The cutting fluid spray pipe 14 is a miniature spray nozzle made of copper alloy or corrosion-resistant stainless steel with an outer diameter of Φ3 to Φ6 mm. The nozzle is fixed to the end side wall of the transverse cutting fluid chamber 12, with its outlet end facing the cutting edge mounting position of the milling cutter head 4. The angle between the nozzle axis and the rotation plane of the cutter head is 15° to 45°. The nozzle integrates a micro fan-shaped nozzle or a double-hole symmetrical nozzle, and the spray coverage width is 1.2 to 1.8 times the diameter of the cutter. The cutting fluid spray pipe 14 and the transverse cutting fluid chamber 12 adopt an O-ring + ferrule type compression sealing structure, so that the integrity of the chamber does not need to be damaged during disassembly.

[0072] The vertical cutting fluid chamber 11 and the horizontal cutting fluid chamber 12 are physically isolated chambers within the milling head housing 1, with no direct through opening between them. They are only connected by the aforementioned built-in flow channel to achieve unidirectional fluid communication. This design avoids disorderly diffusion or stagnation of cutting fluid within the chamber, ensuring controllable flow and a clear path. As an optional implementation, a throttling orifice plate with a thickness of 1-2 mm can be added to the horizontal cutting fluid chamber 12, with a Φ2-Φ4 mm throttling orifice in the center, to regulate the flow rate and pressure towards the cutting fluid spray pipe 14. Alternatively, the cutting fluid inlet pipe 13 can be replaced with an integrated interface module with a solenoid valve to achieve on-demand fluid supply control triggered by the CNC program. Furthermore, the cutting fluid spray pipe 14 can be replaced with an annular spray seat—that is, 3-6 micro-spray holes are evenly distributed around the circumference of the flange at the output end of the horizontal drive assembly 3, arranged around the base of the milling head 4, to improve cooling uniformity.

[0073] The components work together as follows: After the cutting fluid is injected into the vertical cutting fluid chamber 11 through the cutting fluid inlet pipe 13, it flows steadily into the horizontal cutting fluid chamber 12 along the built-in guide channel under the combined action of gravity and system pressure. Due to the limited axial length and narrowing end of the horizontal cutting fluid chamber 12, the fluid is accelerated and maintains a certain dynamic pressure here, and finally is accurately delivered to the contact area between the milling head 4 and the workpiece in the form of atomization or jet through the cutting fluid spray pipe 14. This path design ensures that the cutting fluid has completed pressure stabilization and preliminary sedimentation of impurities before entering the spraying stage, significantly reducing the risk of nozzle clogging. At the same time, because the vertical and horizontal cutting fluid chambers 12 are independently formed and guided, cross-mixing with the circulating coolant in the vertical cooling chamber 5 and the horizontal cooling chamber 6 is completely avoided, ensuring the purity and stability of the cutting fluid composition and meeting the compatibility requirements of various process media such as emulsions, extreme pressure oils, or micro-lubricating MQLs.

[0074] Through the above technical solution, the following can be achieved: A dedicated cutting fluid supply subsystem with a compact structure, clear path, and timely response can be constructed without interfering with the operation of the main cooling system; because the vertical cutting fluid chamber 11 and the horizontal cutting fluid chamber 12 are independently set in separate chambers within the milling head housing 1, and each is equipped with a dedicated inlet and outlet interface, the problem of existing milling heads generally lacking in-situ, directional, and controllable cutting fluid supply capabilities can be solved; because the cutting fluid inlet pipe 13 is located at the top of the cavity and the cutting fluid spray pipe 14 is arranged adjacent to the milling cutter head 4, and the flow channel has no sharp angle bends, the cutting fluid is guaranteed to reach the cutting zone in time, thereby improving chip removal efficiency, suppressing temperature rise in the cutting zone, and improving the surface roughness Ra value of the machined surface by 0.2–0.8 μm; this system can be adapted to various milling cutter heads 4 such as high-speed steel, cemented carbide, and PCD, and is also compatible with dry, wet, and hybrid machining modes, possessing good process adaptability and equipment compatibility.

[0075] Reference Figure 1 , Figure 2A coolant drain pipe 15 is installed on the lower side of the milling head housing 1, and a coolant inlet pipe 16 is installed on the upper end of the milling head housing 1.

[0076] In this embodiment, the coolant drain pipe 15 and the coolant inlet pipe 16 constitute a basic fluid interface system. Its core lies in achieving directional filling and gravity-driven emptying of the coolant through vertical spatial separation. This solves the maintenance problems of traditional milling heads, such as poor coolant filling, residual coolant retention, and incomplete coolant replacement caused by the convergence of coolant inlet and outlet positions and unreasonable layout. This structure can complete coolant replacement under normal operating conditions without relying on external pumps or vacuum assistance, significantly reducing the complexity and time cost of daily maintenance operations.

[0077] The coolant drain pipe 15 is located on the lower side of the milling head housing 1, i.e., at the lowest potential energy point of the cooling circuit when the entire machine is installed. Its axis extends vertically downwards, and the end face of the pipe opening is flush with or slightly lower than the bottom contour of the milling head housing 1, to ensure that the coolant can naturally collect and completely flow out under gravity when stationary. The pipe body is made of corrosion-resistant metal materials such as 304 stainless steel or anodized aluminum alloy, with an inner diameter of Φ8 mm to Φ12 mm and a wall thickness ≥1.0 mm. The end is equipped with a standard threaded interface such as G1 / 4 internal thread or quick-connect fitting for easy connection to an external waste liquid collection container or circulating filter device. (As an optional embodiment, the coolant drain pipe 15 can be integrated with a manual ball valve or an electromagnetic shut-off valve, which is not limited but is a conventional adaptation in the art, for controlling the start and stop of draining; a transparent sight glass section can also be added in the middle of the pipe to facilitate observation of the draining status and whether the residual liquid has been drained.)

[0078] The coolant inlet pipe 16 is located at the upper end of the milling head housing 1, i.e., at the highest potential energy point of the cooling system when the entire machine is installed. Its axis is vertically upward or inclined upward at an angle ≤30°, and the pipe opening is at least 20 mm above the upper limit of the liquid level design at the top of the vertical cooling chamber 5 to reserve a safety air gap and prevent overflow. The pipe body material is the same as the coolant outlet pipe 15, with an inner diameter of Φ6mm~Φ10mm, and the end is equipped with an injection port structure with a sealing cap, or compatible with pressure injection connectors such as DIN 4760 standard quick-change interfaces. In the non-filling state, the pipe opening is sealed by an elastic silicone sealing plug or a screw-in plug with an O-ring to ensure the airtightness and dustproof and waterproof performance of the cooling chamber. As an optional embodiment, the coolant inlet pipe 16 can be extended to the outside of the milling head housing 1 and equipped with a liquid level scale mark, or used in conjunction with a liquid level sensor such as a capacitive liquid level switch to realize the visualization and automated control of the liquid filling process—such extensions do not change the basic structure of this embodiment and conform to the technical evolution path that can be reasonably foreseen by those skilled in the art based on the interface position.

[0079] The relative spatial relationship between the coolant drain pipe 15 and the coolant inlet pipe 16 on the milling head housing 1 constitutes a pair of complementary fluid channels: their axes are arranged approximately vertically opposite each other, with a vertical height difference ≥150 mm. This difference ensures sufficient driving force to overcome the frictional and local resistance generated when the coolant flows through the internal cavities, including the vertical cooling cavity 5, the horizontal cooling cavity 6, and the coolant channel 7. Simultaneously, this height difference also provides a natural siphon start-up condition for the coolant circulation pipe 8. After the initial system filling is completed, this facilitates improved active heat exchange efficiency of the coolant between the vertical and horizontal cavities. Both pipes penetrate the wall of the milling head housing 1 and achieve static sealing through welding, threaded tightening with sealant, or O-ring compression. The sealing rating is not lower than IP54, meeting the long-term reliability requirements under oil mist and cutting fluid splashing environments in machine tool processing environments.

[0080] Through the above technical solution, this application achieves a split-type fluid interface layout with a coolant drain pipe 15 on the lower side and a coolant inlet pipe 16 on the upper side of the milling head housing 1. Since the coolant drain pipe 15 is located at the lowest point and the coolant inlet pipe 16 is located at the highest point, coolant can be injected from top to bottom to fill the entire cooling chamber system, avoiding air resistance and cavities. When the machine is stopped and the coolant is drained, residual liquid automatically flows under gravity and is completely discharged through the coolant drain pipe 15, eliminating low-level liquid accumulation dead zones. Therefore, this structure effectively alleviates the problem of low daily maintenance efficiency caused by inconvenient coolant filling and incomplete waste liquid discharge in the prior art, improving equipment maintenance convenience, cooling system cleanliness, and long-term operational stability.

[0081] Reference Figure 1 One end of the coolant circulation pipe 8 is connected to the upper end of the vertical cooling chamber 5, and the other end is connected to the end of the horizontal cooling chamber 6 near the milling cutter head 4.

[0082] This technical solution constructs a clear and controllable external coolant circulation channel by explicitly defining the coolant circulation path as a unidirectional forced flow: "from the upper end of the vertical cooling chamber → external circulation pipe → near the cutter head end of the horizontal cooling chamber." Its core lies in utilizing the synergistic effect of gravity assistance and the rotational kinetic energy of the drive components to prioritize coolant delivery to the area near the milling cutter head 4, where the heat load is highest and the heat dissipation demand is most urgent, thereby improving local thermal response efficiency. Simultaneously, this arrangement completely avoids the problems of high machining difficulty, high sealing risk, and easy blockage of the flow channel caused by drilling through-hole cooling channels inside the milling head housing 1, significantly enhancing system reliability and manufacturability.

[0083] The coolant circulation pipe 8 is a flexible or rigid tubular component, made of pressure- and corrosion-resistant 304 stainless steel, polytetrafluoroethylene (PTFE), or reinforced nylon composite material. Its inner diameter ranges from Φ4mm to Φ12mm, and its wall thickness is not less than 0.8mm to balance flow requirements and mechanical strength. Both ends of the pipe are detachably and sealed to the upper interface of the vertical cooling chamber 5 and the front interface of the horizontal cooling chamber 6 via quick-connect fittings or O-ring sealed threaded fittings, facilitating future maintenance and replacement. In an optional embodiment, the coolant circulation pipe 8 adopts a double-jacketed structure, with an outer heat insulation layer to suppress the backflow of ambient heat into the coolant flow path and maintain low-temperature stability.

[0084] The upper end of the vertical cooling chamber 5 is provided with an axial outlet with internal threads. The centerline of this outlet coincides with the axis of the vertical cooling chamber 5, ensuring that the coolant is drawn out from the central area at the top of the chamber, avoiding increased turbulence of the liquid surface or the risk of cavitation due to eccentric suction. After the outlet is connected to the inlet end of the coolant circulation pipe 8, a dead-zone-free transition section is formed, with a minimum radius of curvature not less than three times the inner diameter of the pipe, to reduce local pressure loss. In an optional embodiment, a miniature check valve is integrated at the outlet to prevent coolant from flowing back into the vertical cooling chamber 5 and causing abnormal liquid level when the machine is stopped.

[0085] A radial inlet is provided at one end of the transverse cooling chamber 6 near the milling cutter head 4. This inlet is located within the first quarter of the axial length of the transverse cooling chamber 6, and its axis is perpendicular to the axis of the transverse cooling chamber 6 and inclined at 5° to 15° towards the milling cutter head 4. This guides the coolant to be injected tangentially along the inner wall of the transverse cooling chamber 6, enhancing the scouring and cooling effect on the outer edge of the transverse spiral pusher plate 101 and the second balance weight ring 102. The inlet is connected to the outlet end of the coolant circulation pipe 8 through a floating sealing flange, allowing for a certain amount of axial and angular assembly deviation. In an optional embodiment, the inlet is replaced by a porous distributor structure, consisting of 3 to 5 evenly distributed micropores with a single pore diameter of Φ0.6mm to Φ1.2mm, to achieve more uniform coolant distribution.

[0086] There are defined spatial and functional coupling relationships among the aforementioned components: the coolant circulation pipe 8, as a connecting medium independent of the main structural cavity, directly determines the starting and ending points of coolant energy transfer at its two end interfaces; the upper end of the vertical cooling chamber 5 serves as the high-level cold source output end, forming a potential energy difference driving basis with the front end of the horizontal cooling chamber 6 as the low-level heat sink input end; and the positioning of the front end of the horizontal cooling chamber 6 strictly corresponds to the mounting reference surface of the milling cutter head 4, ensuring that the coolant arrival position coincides with the spatial coordinates of the heat source. This layout does not rely on the internal flow channel connection of the vertical drive component 2 or the horizontal drive component 3, nor does it involve the opening and closing control of the coolant channel 7; the cooling strategy guidance is completed solely by defining the physical interface positions.

[0087] Through the above technical solution, this application achieves the following: without changing the basic transmission structure of the milling head and the design of the cooling chamber, the coolant delivery logic can be changed from the traditional "homogeneous circulation" to "targeted supply" simply by adjusting the connection positions of the two ends of the external coolant circulation pipe 8. Since the coolant is drawn out from the upper end of the vertical cooling chamber 5, the liquid level is high, the static pressure is sufficient, and the flow stability is strong. When injected into the transverse cooling chamber 6 near the end of the milling head 4, the fresh low-temperature coolant covers the tool support area and the bearing working area at the end of the transverse worm 31 immediately, effectively suppressing the sudden change in local temperature rise caused by the superposition of cutting heat conduction and frictional heat. Thus, without adding additional power components, introducing complex control logic, or modifying the original sealing structure, the cooling timeliness and temperature field uniformity of key heat-sensitive areas are significantly improved, alleviating the problem of machining accuracy drift caused by thermal deformation.

[0088] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A milling head for a milling machine tool, characterized in that, The milling head housing (1) includes a vertical drive assembly (2) rotatably mounted inside the milling head housing (1) and a horizontal drive assembly (3) rotatably mounted inside the milling head housing (1). The vertical drive assembly (2) is connected to the milling machine tool, and the vertical drive assembly (2) drives the horizontal drive assembly (3) to rotate. A milling cutter head (4) is detachably mounted on the horizontal drive assembly (3). A vertical cooling chamber (5) is provided inside the milling head housing (1), and a horizontal cooling chamber (6) is provided inside the milling head housing (1). The vertical cooling chamber (5) and the horizontal drive assembly (6) are connected to the milling machine tool. A coolant channel (7) is provided on the inner side between the cooling chambers (6), and a coolant circulation pipe (8) is provided on the outer side of the vertical cooling chamber (5) and the horizontal cooling chamber (6). A vertical coolant pushing component (9) is installed on the vertical drive assembly (2), and a horizontal coolant pushing component (10) is installed on the horizontal drive assembly (3). The vertical drive assembly (2) includes a drive connector (21), which is used to connect to the electric spindle of the milling machine tool. A vertical worm gear (22) is installed on the drive connector (21). A vertical turbine (23) is installed on the worm (22). The vertical worm (22) is connected to the vertical cooling chamber (5) through a sealed bearing (51). The vertical coolant propulsion assembly (9) includes a vertical spiral push plate (24) fixed on the vertical worm (22). A first balance weight ring (25) is fixed at both ends of the vertical spiral push plate (24). A plurality of fan-shaped counterweight blocks (251) are installed on the first balance weight ring (25). An axial slider (252) is provided on the lower side of the fan-shaped counterweight block (251). The axial slider (252) An axial threaded rod (253) is installed on the axial slider (252). An axial spring (254) is provided on both sides of the axial slider (252). The axial spring (254) is sleeved on the axial threaded rod (253). A sliding groove (255) is provided on the first balance weight ring (25). The axial threaded rod (253) passes through the sliding groove (255). The axial threaded rod (253) is used to adjust the position of the fan-shaped counterweight (251). One end of the axial spring (254) abuts against the axial slider (252), and the other end abuts against the sliding groove (255).

2. A milling head for a milling machine tool according to claim 1, characterized in that, The lateral drive assembly (3) includes a lateral worm (31) on which a lateral turbine (32) is mounted. The lateral turbine (32) meshes with a vertical turbine (23). The lateral worm (31) is connected to the lateral cooling chamber (6) via a sealed bearing (51).

3. A milling head for a milling machine tool according to claim 2, characterized in that, The transverse coolant propulsion assembly (10) includes a transverse spiral pusher plate (101), and a second counterweight ring (102) is fixed at both ends of the transverse spiral pusher plate (101); the cross section of the transverse spiral pusher plate (101) is a T-shaped structure, and the outer edge of the second counterweight ring (102) and the transverse spiral pusher plate (101) is in contact with the inner wall of the transverse cooling cavity (6).

4. A milling head for a milling machine tool according to claim 3, characterized in that, A guide groove (61) is provided on the inner wall of the transverse cooling chamber (6). The guide groove (61) extends to the side of the sealed bearing (51) near the milling head (4). The guide groove (61) is used to allow the coolant to flow back.

5. A milling head for a milling machine tool according to claim 4, characterized in that, The vertical cooling chamber (5) is equipped with a heat dissipation grille (52). The heat dissipation grille (52) includes a pair of flanges (53) fixed in the vertical cooling chamber (5). A support ring (54) is installed on the flange (53). A positioning strip (55) is fixed on the outside of the support ring (54). A limit groove (56) is opened on the flange (53). The positioning strip (55) is engaged with the limit groove (56). The sealed bearing (51) is engaged with the inner wall of the support ring (54).

6. A milling head for a milling machine tool according to claim 5, characterized in that, The milling head housing (1) is provided with a vertical cutting fluid chamber (11) and a horizontal cutting fluid chamber (12). A cutting fluid inlet pipe (13) is fixed at the upper end of the vertical cutting fluid chamber (11), and a cutting fluid spray pipe (14) is fixed at the end of the horizontal cutting fluid chamber (12) near the milling cutter head (4).

7. A milling head for a milling machine tool according to claim 6, characterized in that, A coolant drain pipe (15) is installed on the lower side of the milling head housing (1), and a coolant inlet pipe (16) is installed on the upper end of the milling head housing (1).

8. A milling head for a milling machine tool according to claim 7, characterized in that, One end of the coolant circulation pipe (8) is connected to the upper end of the vertical cooling chamber (5), and the other end is connected to the end of the horizontal cooling chamber (6) near the milling cutter head (4).

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