Single-pendulum double-servo-drive 3+2 electric spindle swing head

Abstract

The invention discloses a single-pendulum double-servo drive 3 + 2 electric spindle swing head which comprises an upper box body, a lower box body, a spindle box, an electric spindle, a C-axis assembly and an A-axis assembly, the C-axis assembly comprises a C-axis positioning assembly and a C-axis driving assembly, and the A-axis assembly comprises an A-axis positioning assembly and an A-axis driving assembly; the spigot of the upper box body is connected to the bottom end of the ram, the electric spindle is arranged in the spindle box, and the spindle box is of a simple pendulum offset structure; the C-axis positioning assembly comprises an upper crankset, a lower crankset, a C-axis bearing seat and a C-axis counter-pulling mechanism; the C-axis driving assembly comprises a C-axis servo motor and a C-axis speed reducer; the A-axis positioning assembly comprises an A-axis bearing seat, a triple fluted disc assembly and an A-axis oil cylinder; the A-axis driving assembly comprises an A-axis servo motor and an A-axis speed reducer. The swing head integrates a high-power high-speed motorized spindle, a crankset positioning rigidity improving function, a servo driving transposition function and a safe self-locking function, and is low in cost, easy to control, large in A / C shaft driving torque, small in overall size and suitable for 3 + 2 indexing machining.

Description

Technical Field

[0001] This invention belongs to the field of CNC machining centers, specifically relating to a single-swivel dual-servo driven 3+2 electric spindle swivel head for a five-axis machining center, suitable for machining complex curved surfaces in fields such as mold making and aerospace. Background Technology

[0002] Five-axis machining is the ultimate goal of CNC machining centers. With the rapid development of the mold and aerospace industries, the demand for five-axis machining tools is increasing. Five-axis heads using torque motors as direct drive motors for the A / C axes, equipped with high-power, high-speed electric spindles, can achieve high-speed, high-precision five-axis linkage machining. However, the manufacturing cost of torque motor-driven five-axis heads is high, and the large size of the torque motors results in the head occupying more space and being heavier.

[0003] Currently, there is a significant demand in the domestic market for non-linked 3+2 mode electric spindle five-axis heads. These devices utilize a chuck positioning system for the A / C axes and a high-speed, high-power electric spindle. The A and C axes are driven by servo motors, providing high driving force. Compared to linked five-axis heads, servo motor-driven five-axis heads offer advantages such as smaller size, lighter weight, lower manufacturing cost, and simpler control.

[0004] In existing technologies, dual-servo driven 3+2 oscillating heads mainly come in two forms: single-oscillating and double-oscillating. Double-oscillating heads have support and drive structures on both sides of the spindle, resulting in high driving force but also complex structure and large space occupation. Single-oscillating heads only have a support structure on one side of the spindle, resulting in relatively lower driving force, but the spindle is closer to the machining side, offering advantages such as a larger machining space and range, better practicality, and space-saving design. However, traditional single-oscillating heads, while pursuing compact structure and machining range, often suffer from shortcomings in C-axis locking reliability and static safety. For example, their A-axis driving force is insufficient, and traditional C-axis locking structures typically rely on continuous hydraulic pressure, posing a risk of positioning failure in the event of pressure loss. Therefore, how to further improve the reliability, safety, and driving performance of a single-oscillating head while retaining its spatial advantages has become a technical problem that needs to be solved in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a single-swivel dual-servo drive 3+2 electric spindle swivel head that addresses the shortcomings of the prior art. This swivel head integrates a high-power high-speed electric spindle, a toothed sprocket positioning to improve rigidity, and servo drive indexing function. It has low cost, simple control, and large A / C axis drive torque. Compared with direct drive swivel heads of the same specifications, it has a smaller overall size and is a high-efficiency swivel head suitable for 3+2 indexing machining.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a single pendulum dual servo drive 3+2 electric spindle oscillating head, the oscillating head including an upper housing, a lower housing, a spindle box, an electric spindle, a C-axis assembly and an A-axis assembly, the center line of the C-axis assembly (i.e., the center line of the C-axis) is parallel to the center line of the electric spindle, the center line of the A-axis assembly (i.e., the center line of the A-axis) is perpendicular to the center line of the electric spindle, the C-axis assembly includes a C-axis positioning assembly and a C-axis driving assembly, the A-axis assembly includes an A-axis positioning assembly and an A-axis driving assembly, the upper housing stop is connected to the bottom end of the slide block, the electric spindle is set in the spindle box, and the spindle box is a single pendulum bias structure; The C-axis positioning assembly includes an upper sprocket, a lower sprocket, a C-axis bearing housing, and a C-axis reverse pull mechanism. The upper sprocket is centeredly connected to the bottom of the upper housing, and the lower sprocket is connected to the top of the lower housing via a transition ring. The upper part of the C-axis bearing housing is mounted in the upper housing via a needle roller bearing, and the bottom of the C-axis bearing housing is fixed to the lower housing. The C-axis reverse pull mechanism includes multiple pull rod units arranged circumferentially at the bottom of the upper housing. Each pull rod unit includes a pull rod, a disc spring, a C-axis clamping oil chamber, and a C-axis releasing oil chamber. The lower end of the pull rod is connected to the lower housing. The disc spring provides an upward preload to the pull rod so that the lower sprocket is automatically pulled and adhered to the upper sprocket when there is no external hydraulic pressure. The C-axis clamping oil chamber increases the upward clamping force of the pull rod on the lower housing. The C-axis releasing oil chamber drives the pull rod to move downward so that the upper and lower sprockets separate. The C-axis drive assembly includes a C-axis servo motor and a C-axis reducer mounted on the upper housing. The output end of the C-axis servo motor is connected to a gear transmission pair via the C-axis reducer. The C-axis drive assembly is used to drive the lower housing to rotate relative to the upper housing around the center line of the C-axis assembly. The A-axis positioning assembly includes an A-axis bearing housing, a triple gear plate assembly, and an A-axis hydraulic cylinder. The A-axis bearing housing is fixed to the lower housing. The spindle box is swayably mounted on the A-axis bearing housing. The triple gear plate assembly is disposed between the A-axis bearing housing and the spindle box. The A-axis hydraulic cylinder is used to drive the triple gear plate assembly to clamp and release. The A-axis drive assembly includes an A-axis servo motor and an A-axis reducer mounted on the lower housing. The output end of the A-axis servo motor is connected to a multi-stage gear transmission mechanism via the A-axis reducer. The A-axis drive assembly is used to drive the spindle box to swing around the center line of the A-axis assembly.

[0007] This invention's oscillating head uses a servo motor and reducer to drive the A / C axes. Compared to a direct-drive torque motor solution, this significantly reduces manufacturing costs and achieves a smaller overall size and lighter weight, making the oscillating head structure more compact. Simultaneously, the dual servo drive provides a large driving torque, ensuring the power for A / C axis indexing. The single-pendulum offset structure design of the spindle box allows the electric spindle to be closer to the machining sidewall, resulting in a larger machining space, better practicality, and a wider machining range, while saving space occupied by the oscillating head. Furthermore, the C-axis receives preload through disc springs, enabling automatic engagement of the upper and lower sprockets even without external hydraulic pressure (no machining), improving equipment safety and static rigidity, and preventing accidental loosening due to pressure loss in traditional structures. This invention's oscillating head integrates a high-power, high-speed electric spindle, sprocket positioning for improved rigidity, servo-driven indexing, and a safety self-locking function. It is low-cost, simple to control, and provides high A / C axis driving torque. Compared to direct-drive oscillating heads of the same specifications, its overall size is smaller, making it a highly efficient oscillating head suitable for 3+2 indexing machining.

[0008] Preferably, the bottom of the upper housing has multiple stepped holes on its circumference. Each stepped hole contains a first pressure cap, a cylinder sleeve, a sealing cap, a pull sleeve, and a pull rod unit. The pull sleeve of each pull rod unit is located in the space between the inner side of the transition ring and the outer side of the C-axis bearing seat. The bottom of each pull sleeve is a wide-diameter section that extends into the groove at the top of the lower housing and is pressed by the transition ring and the C-axis bearing seat. Each pull rod is threadedly connected to the pull sleeve. The C-axis release oil chamber is formed between the first pressure cap and the top of the pull rod. The C-axis clamping oil chamber is formed between the stepped part of the pull rod and the upper end of the disc spring and the sealing cap. When the C-axis clamping oil chamber is not supplied with oil, under the force of the multiple disc springs, the pull rod drives the lower sprocket, transition ring, and lower housing to move upward through the pull sleeve. The lower sprocket meshes with the upper sprocket, ensuring that the lower sprocket and upper sprocket can mesh even when the head is not machining. When the oscillating head enters the machining state, oil enters the C-axis clamping oil chamber, further increasing the biting force between the upper and lower sprockets, ensuring the oscillating head meets the rigidity required for machining. This design integrates the C-axis reverse pull mechanism, C-axis release oil chamber, and C-axis clamping oil chamber into the stepped hole of the upper housing. Through the compact design of the tie rod, disc spring, and dual oil chambers, it achieves reliable automatic release and release functions for the C-axis while eliminating the structural space occupied by the traditional independent C-axis release and release cylinder structure, making the C-axis structure design more compact and with a higher degree of integration.

[0009] Preferably, the gear transmission pair includes a first transmission gear and a second transmission gear. The first transmission gear is connected to the output end of the C-axis reducer, and the second transmission gear meshes with the first transmission gear and is installed through a floating support structure. The floating support structure includes a spring seat, several small springs, and a flange seat. The spring seat is fixed to the inner hole of the upper housing, the several small springs are disposed on the spring seat, and the flange seat is fixed to the top of the C-axis bearing seat. The second transmission gear is fixed to the flange seat and supported by a thrust roller bearing, which is supported by the several small springs. Since the flange seat and the C-axis bearing seat move up and down with the C-axis clamping, and the C-axis clamping stroke is controlled by the stroke of the hydraulic cylinder in the C-axis counter-clamping mechanism, it is difficult to precisely control the part dimensions. Therefore, this invention, by setting several small springs between the flange seat and the upper housing, allows the second transmission gear and its support structure to be in an axially floating state, thereby effectively compensating for possible interference caused by part movement and dimensional tolerances during the C-axis clamping process and avoiding over-positioning. Meanwhile, the thrust roller bearing converts sliding friction into rolling friction, significantly reducing the driving load during C-axis indexing and making the rotation more stable and smooth.

[0010] When the oscillating head needs to perform the C-axis indexing function, oil enters the C-axis release oil chamber. Under hydraulic pressure, the pull rod drives the pull sleeve to move downwards a distance L1. The lower sprocket, transition ring, lower housing, C-axis bearing seat, second transmission gear, flange seat, and other components simultaneously descend a distance L1 under gravity. After descending, the first and second transmission gears remain engaged. At this point, the upper and lower sprockets disengage, and the C-axis servo motor is energized, providing power to the first transmission gear through the C-axis reducer. This power is then transmitted to the flange seat and C-axis bearing seat via the meshing second transmission gear, thereby driving the lower housing, spindle box, electric spindle, and other components connected to the C-axis bearing seat to rotate together, achieving the C-axis indexing function (i.e., the oscillating head rotates around the centerline of the C-axis assembly). Specifically, the spring seat and small spring in the floating support structure ensure that the thrust roller bearing, flange seat, and second transmission gear can float.

[0011] Preferably, the triple gear assembly includes a positioning gear, an indexing gear, and a piston gear. The positioning gear is fixed to the A-axis bearing housing, the indexing gear is mounted on a rotary seat, and the rotary seat is fixed to the spindle box. The piston gear is axially movable within a transition sleeve, which is fixed to the positioning gear. A first end cap is fixed to the transition sleeve. The A-axis cylinder includes an A-axis piston and a counter-pull seat. The piston gear is fixed to the A-axis piston, and the counter-pull seat is fixed to the indexing gear and moves under hydraulic pressure, allowing the piston gear to simultaneously engage or disengage with both the positioning and indexing gears. The A-axis servo motor provides power to the multi-stage gear transmission mechanism via an A-axis reducer, driving the spindle box and electric spindle to oscillate around the centerline of the A-axis assembly, thus rotating the A-axis. Using a triple gear assembly consisting of a positioning gear, an indexing gear, and a piston gear, in conjunction with the A-axis piston and counter-pull seat, high-precision positioning, high-rigidity machining, and locking of the A-axis can be achieved. In particular, the design of the reverse pull seat ensures that the piston toothed disc can simultaneously and reliably mesh or separate from the positioning toothed disc and the indexing toothed disc, resulting in a large and stable clamping force.

[0012] As a further preferred embodiment, the A-axis hydraulic cylinder includes an A-axis clamping chamber and an A-axis releasing chamber. The A-axis clamping chamber is located between the left side of the first end cover, the step of the reverse pull seat, and the right side of the A-axis piston. The A-axis releasing chamber is located between the step of the transition sleeve and the outer step of the A-axis piston. By setting the A-axis clamping chamber and releasing chamber at specific positions between the first end cover and the A-axis piston, and between the transition sleeve and the A-axis piston, respectively, the clamping and releasing actions of the triple gear assembly are direct and reliable, which is beneficial for achieving rapid and stable A-axis state switching.

[0013] When the oscillating head needs to perform the A-axis rotation function, oil enters the A-axis release oil chamber, the triple gear assembly disengages, and the A-axis servo motor transmits power to the multi-stage gear transmission mechanism through the A-axis reducer, and finally to the spindle box. This drives the rotary table, indexing gear, pull-back seat, electric spindle, and other components to rotate around the A-axis together with the spindle box. When the rotation reaches an integer multiple of the index of the triple gear assembly, the system performs a clamping action. Oil enters the A-axis clamping oil chamber, the triple gear assembly clamps, and thus the A-axis indexing action is completed (i.e., the electric spindle oscillates around the center line of the A-axis assembly).

[0014] As a further preferred embodiment, the spindle box is oscillatingly mounted on the A-axis bearing seat via a first ball bearing, and an oilless bearing is provided between the outer diameter of the right side of the spindle box and the inner hole of the first end cover. When the triple gear assembly is disengaged, the first ball bearing and the oilless bearing jointly bear the radial off-center load of the A-axis. A first ball bearing serves as the main support on one side of the spindle box, while an oilless bearing serves as auxiliary radial positioning on the other side. When the triple gear assembly disengages (A-axis indexing), both bearings jointly bear the radial off-center load of the spindle box and the electric spindle, ensuring the overall rigidity and stability of the oscillating head during oscillation and preventing vibration or accuracy loss caused by cantilever stress.

[0015] Preferably, the multi-stage gear transmission mechanism includes a third, fourth, fifth, and sixth transmission gear that mesh sequentially. The third transmission gear is fixed to the output end of the A-axis reducer via a second end cover. The fourth transmission gear is fixed to the lower housing via a second ball bearing and a second pressure cover. The fifth transmission gear is fixed to the lower housing via a third ball bearing and a third pressure cover. The sixth transmission gear is fixed to the right end of the spindle box. Through the three-stage gear reduction and torque amplification transmission composed of the third, fourth, and fifth transmission gears, the power of the A-axis servo motor is effectively transmitted to the spindle box. This design provides sufficient torque to drive the load to oscillate, offers reliable transmission, and has a compact layout, which helps save space in the lower housing.

[0016] Preferably, the oscillating head further includes a wiring mechanism, which includes a first wiring hole, a second wiring hole, a third wiring hole, and a fourth wiring hole. The first wiring hole is located on the right side of the spindle housing. The second and third wiring holes are respectively located above the lower housing. The fourth wiring hole is located below the protective cover. The protective cover is located inside the slide block and above the C-axis bearing seat. A terminal block is installed on the upper side of the protective cover. A protective cover is installed on the front side of the lower housing. The functional lines of the electric spindle are led out from the first wiring hole, pass through the space between the spindle housing and the protective cover, converge to the second and third wiring holes, then pass through the inner hole of the C-axis bearing seat to the fourth wiring hole, and finally, after being organized by the cable fixing plate, are led out from the terminal block. The above wiring mechanism, through the guidance of multiple wiring holes and the utilization of the space between the spindle housing and the protective cover, provides a spacious, orderly, and protected channel for the functional lines of the electric spindle. The cable management plate design ensures that the cables will not become tangled or excessively bent when the A-axis oscillates, improving cable reliability and lifespan. The cable management space is more spacious than that of a direct-drive oscillating head of the same specifications, fully capable of accommodating the angles required for the rotation of both the A and C axes of the oscillating head.

[0017] Preferably, the A-axis servo motor and A-axis reducer are fixed to the upper right or upper left corner of the lower housing via a mounting plate. This layout makes full use of the space on the side of the lower housing, resulting in a compact structure. It avoids increasing the overall length of the oscillating head by arranging the motor directly behind the spindle box, thus reducing the space occupied by the oscillating head.

[0018] Preferably, the oscillating head further includes an A-axis position detection mechanism and a C-axis position detection mechanism. The A-axis position detection mechanism includes an A-axis signaling block mounted on the lower housing and two A-axis position detection switches for detecting the clamping and releasing positions of the triple-gear assembly. The C-axis position detection mechanism includes a C-axis signaling block mounted on the upper housing and two C-axis position detection switches for detecting the clamping and releasing positions of the upper and lower gear sprockets. By setting the A-axis signaling block and two corresponding A-axis position detection switches on the lower housing, the clamping and releasing states of the triple-gear assembly can be detected and fed back in real time and accurately, thus providing a crucial status confirmation signal for the CNC system, ensuring the safety, reliability, and automation of the A-axis indexing and locking process, and preventing malfunctions. By setting the C-axis signaling block and two corresponding C-axis position detection switches on the upper housing, the clamping and releasing states of the upper and lower gear sprockets can be detected and fed back in real time and accurately, thus ensuring the reliability of the C-axis indexing and clamping process.

[0019] Compared with existing technologies, this invention has the following advantages: The oscillating head of this invention uses a servo motor and reducer to drive the A / C axes. Compared with the direct-drive torque motor solution, this significantly reduces manufacturing costs and achieves a smaller overall size and lighter weight, making the oscillating head structure more compact. Simultaneously, the dual servo drive provides a larger driving torque, ensuring the power for A / C axis indexing. The single-pendulum offset structure design of the spindle box allows the electric spindle to be closer to the machining sidewall, resulting in a larger machining space, better practicality, and a wider machining range, saving space occupied by the oscillating head. Furthermore, the C-axis provides preload through disc springs, enabling automatic engagement of the upper and lower sprockets even without external hydraulic pressure (no machining), improving the safety and static rigidity of the equipment and avoiding accidental loosening due to pressure loss in traditional structures. This invention integrates a high-power, high-speed electric spindle, sprocket positioning for improved rigidity, servo-driven indexing, and a safety self-locking function. It is low-cost, simple to control, and has a large A / C axis driving torque. Compared with direct-drive oscillating heads of the same specifications, its overall size is smaller, making it a highly efficient oscillating head suitable for 3+2 indexing machining. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the single-pendulum dual-servo driven 3+2 electric spindle pendulum head in the embodiment; Figure 2 for Figure 1Enlarged view of point A in the middle; Figure 3 This is a schematic diagram of the power transmission along the A-axis of the oscillating head in the embodiment; Figure 4 Enlarged Figure 3 BB section view; Figures 1-4 The specific reference numerals in the attached figures are as follows: 1-Upper housing, 11-Stepped hole, 12-First pressure plate, 13-Cylinder liner, 14-Sealing cover, 15-Pull sleeve, 16-Wide diameter section, 2-Lower housing, 21-Groove, 22-A-axis signal transmitter, 23-A-axis position detection switch, 24-Protective cover, 25-C-axis signal transmitter, 26-C-axis position detection switch, 3-Spindle box, 31-Electric spindle, 32-First ball bearing, 33-Oil-free bearing 34-Functional pipeline, 41-Upper sprocket, 42-Lower sprocket, 43-C-axis bearing housing, 44-Transition ring, 45-Needle roller bearing, 46-Tie rod, 47-Disc spring, 48-C-axis clamping oil chamber, 49-C-axis releasing oil chamber, 51-C-axis servo motor, 52-C-axis reducer, 53-First transmission gear, 54-Second transmission gear, 55-Spring seat, 56-Small spring, 57-Flange seat. 58-Thrust roller bearing, 61-A-axis bearing housing, 62-Positioning gear plate, 63-Indicating gear plate, 64-Piston gear plate, 65-Rotor seat, 66-Transition sleeve, 67-First end cover, 68-A-axis piston, 681-A-axis clamping oil chamber, 682-A-axis releasing oil chamber, 69-Reverse pull seat, 71-A-axis servo motor, 711-Mounting plate, 72-A-axis reducer, 73-Third transmission gear, 731-Second end cover, 74-Fourth transmission gear, 741-Second ball bearing, 742-Second pressure cap, 75-Fifth transmission gear, 751-Third ball bearing, 752-Third pressure cap, 76-Sixth transmission gear, 81-First wiring hole, 82-Second wiring hole, 83-Third wiring hole, 84-Fourth wiring hole, 85-Protective cover, 86-Terminal block, 87-Wire fixing plate, 9-Slide block. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] Example: A single-pendulum dual-servo driven 3+2 electric spindle oscillating head. Figures 1-4As shown, the oscillating head includes an upper housing 1, a lower housing 2, a spindle housing 3, an electric spindle 31, a C-axis assembly, an A-axis assembly, a wiring mechanism, an A-axis position detection mechanism, and a C-axis position detection mechanism. The centerline of the C-axis assembly is parallel to the centerline of the electric spindle 31, and the centerline of the A-axis assembly is perpendicular to the centerline of the electric spindle 31. The C-axis assembly includes a C-axis positioning assembly and a C-axis drive assembly, and the A-axis assembly includes an A-axis positioning assembly and an A-axis drive assembly. The upper housing 1 is connected to the bottom of the slide block at a stop. The electric spindle 31 is set inside the spindle housing 3, which has a single pendulum bias structure.

[0023] The C-axis positioning assembly includes an upper sprocket 41, a lower sprocket 42, a C-axis bearing housing 43, and a C-axis reverse pull mechanism. The upper sprocket 41 is centeredly connected to the bottom of the upper housing 1, and the lower sprocket 42 is connected to the top of the lower housing 2 via a transition ring 44. The upper part of the C-axis bearing housing 43 is mounted inside the upper housing 1 via a needle roller bearing 45, and the bottom of the C-axis bearing housing 43 is fixed to the lower housing 2. The C-axis reverse pull mechanism includes multiple pull rod units arranged circumferentially at the bottom of the upper housing 1, each pull rod unit containing... Includes a pull rod 46, a disc spring 47, a C-axis clamping oil chamber 48, and a C-axis releasing oil chamber 49. The lower end of the pull rod 46 is connected to the lower housing 2. The disc spring 47 is used to provide an upward preload to the pull rod 46 so that the lower sprocket 42 is automatically pulled and attached to the upper sprocket 41 when there is no external oil pressure. The C-axis clamping oil chamber 48 is used to increase the upward tension of the pull rod 46 on the lower housing 2. The C-axis releasing oil chamber 49 is used to drive the pull rod 46 to move downward so that the upper sprocket 41 and the lower sprocket 42 are separated. Specifically, the bottom of the upper housing 1 has multiple stepped holes 11. Each stepped hole 11 contains a first pressure cap 12, a cylinder sleeve 13, a sealing cap 14, a pull sleeve 15, and a pull rod unit. The pull sleeve 15 of each pull rod unit is located in the space between the inner side of the transition ring 44 and the outer side of the C-axis bearing seat 43. The bottom of each pull sleeve 15 is a wide diameter section 16. The wide diameter section 16 extends into the groove 21 at the top of the lower housing 2 and is pressed by the transition ring 44 and the C-axis bearing seat 43. Each pull rod 46 is threadedly connected to the pull sleeve 15. A C-axis release oil chamber 49 is formed between the first pressure cap 12 and the top of the pull rod 46. A C-axis clamping oil chamber 48 is formed between the stepped part of the pull rod 46 and the disc spring 47 and the upper end of the sealing cap 14.

[0024] The C-axis drive assembly includes a C-axis servo motor 51 and a C-axis reducer 52 mounted on the upper housing 1. The output end of the C-axis servo motor 51 is connected to a gear transmission pair via the C-axis reducer 52. The C-axis drive assembly is used to drive the lower housing 2 to rotate relative to the upper housing 1 around the centerline of the C-axis assembly. The gear transmission pair includes a first transmission gear 53 and a second transmission gear 54. The first transmission gear 53 is connected to the output end of the C-axis reducer 52. The second transmission gear 54 meshes with the first transmission gear 53 and is mounted via a floating support structure. The floating support structure includes a spring seat 55, several small springs 56, and a flange seat 57. The spring seat 55 is fixed to the inner hole of the upper housing 1, the several small springs 56 are disposed on the spring seat 55, and the flange seat 57 is fixed to the top of the C-axis bearing seat 43. The second transmission gear 54 is fixed to the flange seat 57 and supported by a thrust roller bearing 58, which is supported by the several small springs 56. When the C-axis clamping oil chamber 48 is not supplied with oil, under the force of multiple disc springs 47, the pull rod 46 drives the lower sprocket 42, transition ring 44, and lower housing 2 to move upward through the pull sleeve 15. The lower sprocket 42 meshes with the upper sprocket 41, ensuring that the lower sprocket 42 and the upper sprocket 41 can also mesh even when the head is not machining.

[0025] The A-axis positioning assembly includes an A-axis bearing housing 61, a triple gear plate assembly, and an A-axis hydraulic cylinder. The A-axis bearing housing 61 is fixed to the lower housing 2, and the spindle box 3 is swayably mounted on the A-axis bearing housing 61. The triple gear plate assembly is located between the A-axis bearing housing 61 and the spindle box 3. The A-axis hydraulic cylinder is used to drive the triple gear plate assembly to clamp and release. The triple gear assembly includes a positioning gear 62, an indexing gear 63, and a piston gear 64. The positioning gear 62 is fixed to the A-axis bearing seat 61, the indexing gear 63 is mounted on a rotary seat 65, the rotary seat 65 is fixed to the spindle box 3, and the piston gear 64 is axially movable within a transition sleeve 66. The transition sleeve 66 is fixed to the positioning gear 62, and a first end cover 67 is fixed to the transition sleeve 66. The A-axis hydraulic cylinder includes an A-axis piston 68, a pull-back seat 69, an A-axis clamping oil chamber 681, and an A-axis releasing oil chamber 682. The piston gear 64 is fixed to the A-axis piston 68, and the pull-back seat 69 is fixed to the indexing gear 63 and driven by hydraulic pressure. The downward movement allows the piston gear 64 to simultaneously engage or disengage with the positioning gear 62 and the indexing gear 63; the A-axis clamping oil chamber 681 is located between the left side of the first end cover 67, the step of the pull-back seat 69, and the right side of the A-axis piston 68; the A-axis releasing oil chamber 682 is located between the step of the transition sleeve 66 and the outer step of the A-axis piston 68; the spindle box 3 is oscillatingly mounted on the A-axis bearing seat 61 via the first ball bearing 32; an oilless bearing 33 is provided between the outer diameter of the right side of the spindle box 3 and the inner hole of the first end cover 67; when the triple gear assembly is released, the first ball bearing 32 and the oilless bearing 33 jointly bear the radial off-center load of the A-axis. The A-axis position detection mechanism includes an A-axis signaling block 22 mounted on the lower housing 2 and two A-axis position detection switches 23, used to detect the clamping and loosening positions of the triple gear assembly; the C-axis position detection mechanism includes a C-axis signaling block 25 mounted on the upper housing 1 and two C-axis position detection switches 26, used to detect the clamping and loosening positions of the upper gear 41 and the lower gear 42.

[0026] The A-axis drive assembly includes an A-axis servo motor 71 and an A-axis reducer 72, which are fixed to the upper right corner of the lower housing 2 via a mounting plate 711. The output end of the A-axis servo motor 71 is connected to a multi-stage gear transmission mechanism via the A-axis reducer 72. The A-axis drive assembly is used to drive the spindle box 3 to swing around the center line of the A-axis assembly. The multi-stage gear transmission mechanism includes a third transmission gear 73, a fourth transmission gear 74, a fifth transmission gear 75, and a sixth transmission gear 76 that mesh sequentially. The third transmission gear 73 is fixed to the output end of the A-axis reducer 72 via a second end cover 731. The fourth transmission gear 74 is fixed to the lower housing 2 via a second ball bearing 741 and a second pressure cover 742. The fifth transmission gear 75 is fixed to the lower housing 2 via a third ball bearing 751 and a third pressure cover 752. The sixth transmission gear 76 is fixed to the right end of the spindle box 3.

[0027] The wiring mechanism includes a first wiring hole 81, a second wiring hole 82, a third wiring hole 83, and a fourth wiring hole 84. The first wiring hole 81 is located on the right side of the spindle box 3. The second wiring hole 82 and the third wiring hole 83 are respectively located above the lower housing 2. The fourth wiring hole 84 is located below the protective cover 85. The protective cover 85 is located inside the slide 9 and above the C-axis bearing seat 43. A terminal block 86 is installed on the upper side of the protective cover 85. A protective cover 24 is installed on the front side of the lower housing 2. The functional pipeline 34 of the electric spindle 31 is led out from the first wiring hole 81, passes through the space between the spindle box 3 and the protective cover 24, gathers at the second wiring hole 82 and the third wiring hole 83, then passes through the inner hole of the C-axis bearing seat 43 to the fourth wiring hole 84, and finally is led out from the terminal block 86 after being organized by the cable fixing plate 87.

[0028] When the oscillating head needs to perform the C-axis indexing function, the C-axis releases oil chamber 49 to allow oil to enter. Under the action of oil pressure, the pull rod 46 drives the pull sleeve 15 to move downward by a distance L1. The lower sprocket 42, transition ring 44, lower housing 2, C-axis bearing seat 43, second transmission gear 54, flange seat 57 and other components descend simultaneously by a distance L1 under the action of gravity. After descending, the first transmission gear 53 and the second transmission gear 54 are still in a meshing state. At this time, the upper sprocket 41 and the lower sprocket 42 disengage. At the same time, the C-axis servo motor 51 is energized and provides power to the first transmission gear 53 through the C-axis reducer 52. The power is transmitted to the flange seat 57 and the C-axis bearing seat 43 through the second transmission gear 54 that meshes with it. This causes the lower housing 2, spindle box 3, electric spindle 31 and other components connected to the C-axis bearing seat 43 to rotate together, realizing the C-axis indexing function and making the oscillating head rotate around the center line of the C-axis assembly. Specifically, the spring seat 55 and small springs 56 in the floating support structure ensure that components such as the thrust roller bearing 58, flange seat 57, and second transmission gear 54 can float. Since the flange seat 57 and C-axis bearing seat 43 move up and down with the C-axis clamping, and the C-axis clamping stroke is controlled by the cylinder stroke in the C-axis counter-pulling mechanism, it is difficult to accurately control the part dimensions. Therefore, this invention sets several small springs 56 between the flange seat 57 and the upper housing 1, so that the second transmission gear 54 and its support structure are in an axial floating state, thereby effectively compensating for the interference that may occur due to the movement and dimensional tolerances of the parts during the C-axis clamping process and avoiding over-positioning.

[0029] When the oscillating head needs to perform the A-axis rotation function, oil enters the A-axis release oil chamber 682, the triple gear assembly disengages, and the A-axis servo motor 71 transmits power to the multi-stage gear transmission mechanism through the A-axis reducer 72, and finally to the spindle box 3. This drives the rotary seat 65, indexing gear 63, pull-back seat 69, electric spindle 31, and other components to rotate around the A-axis together with the spindle box 3. When the rotation reaches an integer multiple of the index of the triple gear assembly, the system performs a clamping action. Oil enters the A-axis clamping oil chamber 681, the triple gear assembly clamps, and the A-axis indexing action is completed, causing the electric spindle 31 to oscillate around the center line of the A-axis assembly.

Claims

1. A single-pendulum dual-servo driven 3+2 electric spindle oscillating head, characterized in that, The oscillating head includes an upper housing, a lower housing, a spindle box, an electric spindle, a C-axis assembly, and an A-axis assembly. The centerline of the C-axis assembly is parallel to the centerline of the electric spindle, and the centerline of the A-axis assembly is perpendicular to the centerline of the electric spindle. The C-axis assembly includes a C-axis positioning assembly and a C-axis drive assembly, and the A-axis assembly includes an A-axis positioning assembly and an A-axis drive assembly. The upper housing is connected to the bottom of the slide block at a stop. The electric spindle is housed inside the spindle box, which is a single pendulum bias structure. The C-axis positioning assembly includes an upper sprocket, a lower sprocket, a C-axis bearing housing, and a C-axis reverse pull mechanism. The upper sprocket is centeredly connected to the bottom of the upper housing, and the lower sprocket is connected to the top of the lower housing via a transition ring. The upper part of the C-axis bearing housing is mounted in the upper housing via a needle roller bearing, and the bottom of the C-axis bearing housing is fixed to the lower housing. The C-axis reverse pull mechanism includes multiple pull rod units arranged circumferentially at the bottom of the upper housing. Each pull rod unit includes a pull rod, a disc spring, a C-axis clamping oil chamber, and a C-axis releasing oil chamber. The lower end of the pull rod is connected to the lower housing. The disc spring provides an upward preload to the pull rod so that the lower sprocket is automatically pulled and adhered to the upper sprocket when there is no external hydraulic pressure. The C-axis clamping oil chamber increases the upward clamping force of the pull rod on the lower housing. The C-axis releasing oil chamber drives the pull rod to move downward so that the upper and lower sprockets separate. The C-axis drive assembly includes a C-axis servo motor and a C-axis reducer mounted on the upper housing. The output end of the C-axis servo motor is connected to a gear transmission pair via the C-axis reducer. The C-axis drive assembly is used to drive the lower housing to rotate relative to the upper housing around the center line of the C-axis assembly. The A-axis positioning assembly includes an A-axis bearing housing, a triple gear plate assembly, and an A-axis hydraulic cylinder. The A-axis bearing housing is fixed to the lower housing. The spindle box is swayably mounted on the A-axis bearing housing. The triple gear plate assembly is disposed between the A-axis bearing housing and the spindle box. The A-axis hydraulic cylinder is used to drive the triple gear plate assembly to clamp and release. The A-axis drive assembly includes an A-axis servo motor and an A-axis reducer mounted on the lower housing. The output end of the A-axis servo motor is connected to a multi-stage gear transmission mechanism via the A-axis reducer. The A-axis drive assembly is used to drive the spindle box to swing around the center line of the A-axis assembly.

2. The single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 1, characterized in that, The upper housing has multiple stepped holes on its bottom circumference. Each stepped hole contains a first pressure cap, a cylinder sleeve, a sealing cap, a pull sleeve, and a pull rod unit. The pull sleeve of each pull rod unit is located in the space between the inner side of the transition ring and the outer side of the C-axis bearing seat. The bottom of each pull sleeve is a wide-diameter section that extends into the groove at the top of the lower housing and is pressed by the transition ring and the C-axis bearing seat. Each pull rod is threaded to the pull sleeve. The first pressure cap and the top of the pull rod form the C-axis release oil chamber. The stepped part of the pull rod and the upper end of the disc spring and the sealing cap form the C-axis clamping oil chamber.

3. The single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 1, characterized in that, The gear transmission pair includes a first transmission gear and a second transmission gear. The first transmission gear is connected to the output end of the C-axis reducer. The second transmission gear meshes with the first transmission gear and is installed through a floating support structure. The floating support structure includes a spring seat, several small springs, and a flange seat. The spring seat is fixed to the inner hole of the upper housing. The several small springs are disposed on the spring seat. The flange seat is fixed to the top of the C-axis bearing seat. The second transmission gear is fixed to the flange seat and supported by a thrust roller bearing, which is supported by the several small springs.

4. The single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 1, characterized in that, The triple gear assembly includes a positioning gear, an indexing gear, and a piston gear. The positioning gear is fixed to the A-axis bearing housing, the indexing gear is mounted on a rotary seat, the rotary seat is fixed to the spindle box, and the piston gear is axially movable within a transition sleeve. The transition sleeve is fixed to the positioning gear and has a first end cap. The A-axis cylinder includes an A-axis piston and a counter-pull seat. The piston gear is fixed to the A-axis piston, and the counter-pull seat is fixed to the indexing gear and moves under hydraulic pressure, allowing the piston gear to simultaneously engage or disengage with both the positioning gear and the indexing gear.

5. A single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 4, characterized in that, The A-axis hydraulic cylinder includes an A-axis clamping oil chamber and an A-axis releasing oil chamber. The A-axis clamping oil chamber is located between the left side of the first end cover, the step of the reverse pull seat, and the right side of the A-axis piston. The A-axis releasing oil chamber is located between the step of the transition sleeve and the outer step of the A-axis piston.

6. A single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 4, characterized in that, The spindle box is oscillatingly mounted on the A-axis bearing seat via a first ball bearing. An oilless bearing is provided between the outer diameter of the right side of the spindle box and the inner hole of the first end cover. When the triple gear assembly is released, the first ball bearing and the oilless bearing jointly bear the radial off-center load of the A-axis.

7. A single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 1, characterized in that, The multi-stage gear transmission mechanism includes a third transmission gear, a fourth transmission gear, a fifth transmission gear, and a sixth transmission gear that mesh sequentially. The third transmission gear is fixed to the output end of the A-axis reducer via a second end cover. The fourth transmission gear is fixed to the lower housing via a second ball bearing and a second pressure cover. The fifth transmission gear is fixed to the lower housing via a third ball bearing and a third pressure cover. The sixth transmission gear is fixed to the right end of the main shaft housing.

8. A single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 1, characterized in that, The oscillating head also includes a wiring mechanism, which includes a first wiring hole, a second wiring hole, a third wiring hole, and a fourth wiring hole. The first wiring hole is located on the right side of the spindle box. The second and third wiring holes are respectively located above the lower housing. The fourth wiring hole is located below the protective cover. The protective cover is located inside the slide block and above the C-axis bearing seat. A terminal block is installed on the upper side of the protective cover. A protective cover is installed on the front side of the lower housing. The functional lines of the electric spindle are led out from the first wiring hole, pass through the space between the spindle box and the protective cover, converge to the second and third wiring holes, then pass through the inner hole of the C-axis bearing seat to the fourth wiring hole, and finally, after being organized by the cable fixing plate, are led out from the terminal block.

9. A single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 1, characterized in that, The A-axis servo motor and A-axis reducer are fixed to the upper right or upper left corner of the lower housing via a mounting plate.

10. A single-pendulum dual-servo driven 3+2 electric spindle oscillating head according to claim 1, characterized in that, The oscillating head also includes an A-axis position detection mechanism and a C-axis position detection mechanism. The A-axis position detection mechanism includes an A-axis signaling block installed on the lower housing and two A-axis position detection switches, used to detect the clamping and releasing positions of the triple gear assembly. The C-axis position detection mechanism includes a C-axis signaling block installed on the upper housing and two C-axis position detection switches, used to detect the clamping and releasing positions of the upper and lower gears.

Images