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

Abstract

The invention discloses a single-pendulum single-servo-drive 3 + 2 motorized spindle swing head which comprises an upper box body, a lower box body, a spindle box, a motorized spindle, a C-axis assembly, an A-axis assembly and a transmission assembly, the C-axis assembly comprises a C-axis positioning assembly and a C-axis driving assembly, the A-axis assembly comprises an A-axis positioning assembly and an A-axis driving assembly, a spigot of the upper box body is connected to the bottom end of a ram, the motorized spindle is arranged in the spindle box, and the transmission assembly is arranged in the lower box body. The spindle box is of a simple pendulum offset structure; and the C-axis driving assembly and the A-axis driving assembly share one set of servo motor and speed reducer. The swing head integrates a high-power high-speed motorized spindle, a crankset positioning function for improving rigidity, a single-servo driving double-shaft transposition function and a safe self-locking function, and realizes synchronous reduction of manufacturing cost and use cost, remarkable simplification of control logic and synchronous improvement of structural compactness and reliability. Compared with a double-servo-drive or direct-drive swing head of the same specification, the swing head has the outstanding advantages in the aspects of cost, size, control and safety, and is particularly suitable for 3 + 2 indexing machining.

Description

A single pendulum single servo driven 3+2 electric spindle oscillating head Technical Field

[0001] This invention belongs to the field of CNC machining centers, specifically relating to a single-pendulum single-servo driven 3+2 electric spindle oscillating 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] The disc positioning and high-speed, high-power electric spindle, with servo motors driving the A and C axes, provide a large driving force. Compared with a five-axis linkage head, the servo motor-driven five-axis head has advantages such as small size, light weight, lower manufacturing cost, and simple 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, bringing the spindle closer to the machining side and offering advantages such as larger machining space and range, making them more practical and saving space. However, their A-axis driving force is relatively small, and traditional C-axis locking structures typically rely on continuous hydraulic pressure, posing a risk of positioning failure in the event of pressure loss. Furthermore, regardless of whether it's a double-oscillating or traditional single-oscillating structure, the A and C axes usually require independent servo motors and drive systems, resulting in a large number of servo motors in the entire machine, leaving room for optimization in cost control and structural integration. Therefore, how to further reduce the number of servo motors and lower costs while retaining the space and cost advantages of the single-oscillating structure, and simultaneously improve its drive reliability and locking safety, has become a noteworthy technical issue in this field. Summary of the Invention

[0005] The technical problem this invention aims to solve is to address the shortcomings of existing technologies by providing a single-oscillator, single-servo-driven 3+2 electric spindle oscillator head. This oscillator head integrates a high-power, high-speed electric spindle, a toothed sprocket for improved rigidity, and a single-servo-driven dual-axis indexing mechanism with a safety self-locking function. This achieves simultaneous reductions in manufacturing and operating costs, significant simplification of control logic, and simultaneous improvements in structural compactness and reliability. Compared to dual-servo-driven or direct-drive oscillator heads of the same specifications, this invention offers significant advantages in cost, size, control, and safety, making it a high-performance, high-reliability, and high-efficiency oscillator head particularly suitable for 3+2 indexing machining.

[0006] The technical solution adopted by this invention to solve the above-mentioned technical problems is as follows: a single-pendulum single-servo driven 3+2 electric spindle oscillating head, the oscillating head including an upper housing, a lower housing, a spindle housing, an electric spindle, a C-axis assembly, an A-axis assembly, and a transmission 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 stop is connected to the bottom end of the slide block, and the electric spindle is disposed inside the spindle housing. The spindle box has a single-pendulum bias structure; the C-axis drive assembly and the A-axis drive assembly share a set of servo motor and reducer installed on the upper housing. The output end of the reducer is connected to a gear transmission pair. The transmission assembly includes a bevel gear pair and a multi-stage gear transmission mechanism. The bevel gear pair is poweredly connected to the gear transmission pair, and the multi-stage gear transmission mechanism is poweredly connected to the bevel gear pair. 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 drive assembly is used to drive the spindle box to swing around the center line of the A-axis assembly. The C-axis positioning assembly includes an upper sprocket, a lower sprocket, 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 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, and the disc spring provides an upward preload to the pull rod so that the lower sprocket is automatically pulled and fitted against the upper sprocket when no external hydraulic pressure is applied. The C-axis clamping oil chamber is used to increase the upward tension of the pull rod on the lower housing, and the C-axis releasing oil chamber is used to drive the pull rod to move downward so that the upper and lower gears are separated. The A-axis positioning assembly includes an A-axis bearing housing, a triple gear assembly, and an A-axis cylinder. The A-axis bearing housing is fixed to the lower housing, and the spindle box is swayably mounted on the A-axis bearing housing. The triple gear assembly is disposed between the A-axis bearing housing and the spindle box. The A-axis cylinder is used to drive the triple gear assembly to clamp and release. The triple gear assembly is connected to the multi-stage gear transmission mechanism.

[0007] This invention's oscillating head uses a single servo motor and reducer to collaboratively drive both the A and C axes. Compared to existing dual-servo motor drive solutions, the number of servo motors and associated control systems is halved, significantly reducing the procurement cost of core electrical components and the overall manufacturing cost. Furthermore, compared to direct-drive torque motor solutions, this invention's oscillating head achieves greater driving torque while offering more significant cost advantages and a more compact structure.

[0008] The A / C axes of the oscillating head of this invention share a single drive source, which not only reduces electrical wiring and simplifies the control system architecture, but also avoids the synchronization and interference problems that may exist with dual motors, reducing system complexity and failure rate, and improving reliability. The transmission components are integrated inside the upper and lower housings, playing a role in transmission and power distribution, achieving a smaller overall size and lighter weight, making the oscillating head structure more compact.

[0009] The single-pendulum offset structure design of the spindle box allows the electric spindle to be closer to the machining side wall, resulting in a larger machining space. It is highly practical, has a wide machining range, and effectively saves the space occupied by the pendulum head on the machine tool.

[0010] Furthermore, in terms of positioning and locking, the C-axis reverse pull mechanism provides preload through disc springs, enabling the upper and lower gears to automatically maintain engagement even without external hydraulic pressure (no machining). This significantly improves the safety and static rigidity of the equipment, preventing accidental loosening that may occur due to pressure loss in traditional structures. The A-axis employs a high-rigidity triple gear assembly and an A-axis hydraulic cylinder drive, ensuring high precision and rigidity in swing positioning.

[0011] This invention integrates a high-power, high-speed electric spindle, a toothed sprocket for enhanced rigidity, and a single-servo-driven dual-axis indexing mechanism with a safety self-locking function. This achieves simultaneous reductions in manufacturing and operating costs, significant simplification of control logic, and simultaneous improvements in structural compactness and reliability. Compared to dual-servo-driven or direct-drive spindles of the same specifications, this invention offers significant advantages in cost, size, control, and safety, making it a high-performance, high-reliability, and high-efficiency spindle particularly suitable for 3+2 indexing machining.

[0012] Preferably, the bevel gear pair includes a meshing first bevel gear and a second bevel gear. The centerline of the first bevel gear coincides with the centerline of the C-axis assembly, and the centerline of the second bevel gear is parallel to the centerline of the A-axis assembly. The first bevel gear is centered and mounted on the lower housing via a first bearing seat, and the second bevel gear is centered and mounted on the lower housing via a second bearing seat. The first bearing seat is fixed to the upper part of the lower housing via a first ball bearing and a first end cap, and the second bearing seat is fixed to the upper part of the lower housing via a second ball bearing and a second end cap. The second bevel gear is poweredly connected to the multi-stage gear transmission mechanism. The orthogonal first and second bevel gears spatially divide the power from the servo motor into two directions, ensuring the rotation of the lower housing and the oscillation of the spindle box, which is key to achieving this single-motor-driven dual-axis spatial layout.

[0013] As a further preferred embodiment, the gear transmission pair includes a meshing first transmission gear and a second transmission gear. The first transmission gear is connected to the output end of the reducer, and the second transmission gear meshes with the first transmission gear and is mounted via 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 first bevel gear, and 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 first bevel gear 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. At the same time, the thrust roller bearing converts sliding friction into rolling friction, which significantly reduces the driving load during C-axis indexing, making the rotation action more stable and smooth.

[0014] When the oscillating head needs to perform the C-axis indexing function, the C-axis releases the oil chamber to allow oil to enter. Under the action of oil pressure, the pull rod drives the pull sleeve to move downward by a distance L1. The lower sprocket, transition ring, lower housing, first bevel gear, second transmission gear, flange seat and other components descend simultaneously by a distance L1 under the action of gravity. After descending, it can still ensure that the first transmission gear and the second transmission gear are in a meshing state. At this time, the upper sprocket and the lower sprocket disengage, and it is necessary to ensure that the A-axis hydraulic cylinder drives the triple gear assembly in a clamping state. After completing the above two steps, the servo motor is powered on and provides power to the first transmission gear through the reducer. The power is then transmitted to the first bevel gear through the second transmission gear meshing with it, and then to the multi-stage gear transmission mechanism and the triple gear assembly through the second bevel gear. Finally, the power is transmitted to the lower housing. At this time, the rotation of the A-axis and the second bevel gear is restricted. The servo motor continues to provide indexing power, causing the second bevel gear to perform a large rotation around the center line of the C-axis assembly around the first bevel gear. The lower housing, spindle box, and electric spindle move together. After rotating to the required angle, oil enters the C-axis clamping oil chamber, and the upper and lower gears mesh, realizing the C-axis indexing function (i.e., the oscillating head rotates around the center line of the C-axis assembly).

[0015] As a further preferred embodiment, the multi-stage gear transmission mechanism includes a third transmission gear, a fourth transmission gear, and a fifth transmission gear meshing sequentially. The third transmission gear is coaxially fixed to the second bevel gear. The fourth transmission gear is fixed to the spindle box via a snap ring, a third ball bearing, and a third end cover, and is located below the third transmission gear. The fifth transmission gear is fixed to the right end of the spindle box, and is located below the fourth transmission gear. This multi-stage gear transmission mechanism is compact and can reduce the power input from the second bevel gear while amplifying the output torque. This ensures that a single servo motor has sufficient torque to drive the spindle box and electric spindle to oscillate stably and reliably around the A-axis, meeting the requirements for A-axis driving force during machining.

[0016] As a further preferred embodiment, the bottom of the upper housing has multiple stepped holes on its circumference. Each stepped hole contains a 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 first 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 first bearing seat. Each pull rod is threadedly connected to the pull sleeve. The pressure cap and the top of the pull rod form the C-axis release oil chamber, and 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. 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, the transition ring, and the lower housing to move upward through the pull sleeve. The lower sprocket meshes with the upper sprocket, ensuring that the lower sprocket and the upper sprocket can mesh even when the head is not machining. When the C-axis enters the machining locking state, oil enters the C-axis clamping oil chamber, further increasing the meshing 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 pull 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.

[0017] Preferably, the triple-gear assembly includes a positioning gear plate, a rotating gear plate, and a piston gear plate. The positioning gear plate is fixed to the A-axis bearing housing, the rotating gear plate is mounted on a rotary seat, and the rotary seat is fixed to the spindle box. The piston gear plate is axially movable within a transition sleeve, which is fixed to the positioning gear plate. A fourth end cap is fixed to the transition sleeve. The A-axis hydraulic cylinder includes an A-axis piston and a counter-pull seat. The piston gear plate is fixed to the A-axis piston, and the counter-pull seat is fixed to the rotating gear plate and actuates under hydraulic pressure, allowing the piston gear plate to simultaneously engage or disengage with the positioning and rotating gear plates. When the upper and lower gear plates are engaged and the piston gear plate is disengaged from the positioning and rotating gear plates, the servo motor provides power to the multi-stage gear transmission mechanism via a reducer, driving the spindle box and electric spindle to oscillate around the centerline of the A-axis assembly, thus rotating the A-axis. The system employs a triple gear assembly consisting of a positioning gear plate, an indexing gear plate, and a piston gear plate, which, in conjunction with the A-axis piston and a reverse pull seat, enables high-precision positioning, high-rigidity machining, and locking of the A-axis. The reverse pull seat design, in particular, ensures that the piston gear plate can simultaneously and reliably mesh or disengage with both the positioning and indexing gear plates, resulting in a large and stable clamping force.

[0018] 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 fourth 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 positioning the A-axis clamping chamber and the releasing chamber at specific positions between the fourth 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, facilitating rapid and stable A-axis state switching.

[0019] When the oscillating head needs to perform the A-axis rotation function, the upper and lower sprockets mesh, oil enters the A-axis release oil chamber, and the A-axis piston drives the piston gear plate to move to the right. After the three-gear plate assembly completes the release action, the servo motor transmits power to the multi-stage gear transmission mechanism through the reducer, and finally to the spindle box, which in turn drives the rotary table, indexing gear plate, 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 three-gear plate assembly, the system performs the clamping action, oil enters the A-axis clamping oil chamber, the three-gear plate assembly clamps, and thus completes the A-axis indexing action (i.e., the electric spindle oscillates around the center line of the A-axis assembly).

[0020] As a further preferred embodiment, the spindle box is oscillatingly mounted on the A-axis bearing seat via a fourth 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 fourth end cover. When the triple gear assembly is disengaged, the fourth ball bearing and the oilless bearing jointly bear the radial off-center load of the A-axis. A fourth 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 due to cantilever stress.

[0021] Preferably, the oscillating head further includes a wiring mechanism, which includes a first wiring hole, a second wiring hole, a third wiring hole, a fourth wiring hole, and a fifth 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 on the upper side of the lower housing. The fourth wiring hole is located on the top of the lower housing. The fifth wiring hole is located below the protective cover. The protective cover is located inside the slide block and above the bevel gear pair. 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 enter the inner hole of the bevel gear pair through the fourth wiring hole, and then enter the fifth wiring hole. Finally, after being organized by the wire fixing plate, they are led out from the terminal block. The aforementioned wiring mechanism, through the guidance of multiple wiring holes and the utilization of the space between the spindle box and the protective cover, provides a spacious, orderly, and protected passage for the functional pipelines of the electric spindle. The design of the cable holder ensures that the pipelines will not tangle or bend excessively during A-axis oscillation, improving the reliability and lifespan of the wiring. Due to the use of a single servo drive and a compact transmission layout, the wiring space is more generous than that of a direct-drive oscillating head of the same specification, fully capable of meeting the angle requirements of the oscillating head's A and C axes rotation.

[0022] 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.

[0023] Compared with existing technologies, this invention has the following advantages: The oscillating head of this invention uses a single servo motor and reducer to collaboratively drive both the A and C axes. Compared to existing dual-servo motor drive schemes, the number of servo motors and supporting control systems is halved, significantly reducing the procurement cost of core electrical components and the overall manufacturing cost. Simultaneously, compared to direct-drive torque motor schemes, the oscillating head of this invention achieves greater driving torque while exhibiting more prominent cost advantages and structural compactness. The single-oscillating offset structure design of the spindle box allows the electric spindle to be closer to the machining sidewall, obtaining a larger machining space, strong practicality, and a wide machining range, effectively saving space occupied by the oscillating head on the machine tool. Furthermore, the C-axis reverse tension mechanism provides preload through disc springs, achieving automatic engagement of the upper and lower gears even without external hydraulic pressure (no machining), greatly improving the safety and static rigidity of the equipment and avoiding accidental loosening due to pressure loss that may occur in traditional structures. The A-axis uses a high-rigidity triple-gear assembly and A-axis hydraulic cylinder drive, ensuring high precision and high rigidity in the oscillating positioning. This invention integrates a high-power, high-speed electric spindle, a toothed sprocket for enhanced rigidity, and a single-servo-driven dual-axis indexing mechanism with a safety self-locking function. This achieves simultaneous reductions in manufacturing and operating costs, significant simplification of control logic, and simultaneous improvements in structural compactness and reliability. Compared to dual-servo-driven or direct-drive spindles of the same specifications, this invention offers significant advantages in cost, size, control, and safety, making it a high-performance, high-reliability, and high-efficiency spindle particularly suitable for 3+2 indexing machining. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the power transmission of the single pendulum single servo driven 3+2 electric spindle oscillating head in the embodiment; Figure 2 is a cross-sectional view of the single pendulum single servo driven 3+2 electric spindle oscillating head in the embodiment; Figure 3 is an enlarged view of point A in Figure 2; the specific reference numerals in Figures 1-3 are as follows: 1-upper housing, 11-stepped hole, 12-pressure cover, 13-cylinder liner, 14-sealing cover, 15-pull sleeve, 16-wide diameter section, 17-servo motor, 18-reducer, 19-slide block, 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, 27-Spindle box, 28-Electric spindle, 31-Upper sprocket, 32-Lower sprocket, 33-Transition ring, 34-Tie rod, 35-Disc spring, 36-C-axis clamping oil chamber, 37-C-axis releasing oil chamber, 38-Fourth ball bearing, 39-Oil-free bearing, 30-Functional pipeline, 41-A-axis bearing housing, 42- A-axis piston, 43-A-axis clamping oil chamber, 44-A-axis releasing oil chamber, 45-reverse pull seat, 51-first bevel gear, 52-second bevel gear, 53-first bearing seat, 54-second bearing seat, 55-first ball bearing, 56-first end cover, 57-second ball bearing, 58-second end cover, 61-first transmission gear, 62-second transmission gear, 63-third transmission gear, 64-fourth transmission gear, 65-fifth transmission gear, 66-circlip, 6 7-Third ball bearing, 68-Third end cover, 71-Spring seat, 72-Small spring, 73-Flange seat, 74-Thrust roller bearing, 81-First wiring hole, 82-Second wiring hole, 83-Third wiring hole, 84-Fourth wiring hole, 85-Fifth wiring hole, 86-Protective cover, 87-Terminal block, 88-Wire fixing plate, 91-Positioning gear plate, 92-Indexing gear plate, 93-Piston gear plate, 94-Rotor, 95-Transition sleeve, 96-Fourth end cover. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] Example: A single pendulum single servo driven 3+2 electric spindle oscillating head, as shown in Figures 1-3, the oscillating head includes an upper housing 1, a lower housing 2, a spindle housing 27, an electric spindle 28, a C-axis assembly, an A-axis assembly, a transmission 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 28, and the centerline of the A-axis assembly is perpendicular to the centerline of the electric spindle 28. 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 end of the slide ram 19. The electric spindle 28 is set inside the spindle housing 27, which is a single pendulum bias structure.

[0027] The C-axis drive assembly and the A-axis drive assembly share a set of servo motor 17 and reducer 18 mounted on the upper housing 1. The output end of the reducer 18 is connected to the gear transmission pair. The transmission assembly includes a bevel gear pair and a multi-stage gear transmission mechanism. The bevel gear pair is poweredly connected to the gear transmission pair, and the multi-stage gear transmission mechanism is poweredly connected to the bevel gear pair. The C-axis drive assembly is used to drive the lower housing 2 to rotate relative to the upper housing 1 around the center line of the C-axis assembly. The A-axis drive assembly is used to drive the spindle box 27 to swing around the center line of the A-axis assembly.

[0028] The C-axis positioning assembly includes an upper sprocket 31, a lower sprocket 32, and a C-axis reverse pull mechanism. The upper sprocket 31 is centeredly connected to the bottom of the upper housing 1, and the lower sprocket 32 ​​is connected to the top of the lower housing 2 via a transition ring 33. 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 includes a pull rod 34, a disc spring 35, a C-axis clamping oil chamber 36, and a C-axis releasing oil chamber 37. The lower end of the pull rod 34 is connected to the lower housing 2. The disc spring 35 is used to provide an upward preload to the pull rod 34 so that the lower sprocket 32 ​​is automatically pulled and adhered to the upper sprocket 31 when there is no external hydraulic pressure. The C-axis clamping oil chamber 36 is used to increase the upward clamping force of the pull rod 34 on the lower housing 2. The C-axis releasing oil chamber 37 is used to drive the pull rod 34 to move downward so that the upper sprocket 31 and the lower sprocket 32 ​​are separated.

[0029] The A-axis positioning assembly includes an A-axis bearing housing 41, a triple gear plate assembly, and an A-axis hydraulic cylinder. The A-axis bearing housing 41 is fixed to the lower housing 2, and the spindle box 27 is swayably mounted on the A-axis bearing housing 41. The triple gear plate assembly is located between the A-axis bearing housing 41 and the spindle box 27. The A-axis hydraulic cylinder is used to drive the triple gear plate assembly to clamp and release. The triple gear plate assembly is connected to a multi-stage gear transmission mechanism.

[0030] The bevel gear pair includes a meshing first bevel gear 51 and a second bevel gear 52. The centerline of the first bevel gear 51 coincides with the centerline of the C-axis assembly, and the centerline of the second bevel gear 52 is parallel to the centerline of the A-axis assembly. The first bevel gear 51 is centered and mounted on the lower housing 2 via a first bearing seat 53, and the second bevel gear 52 is centered and mounted on the lower housing 2 via a second bearing seat 54. The first bearing seat 53 is fixed to the upper part of the lower housing 2 via a first ball bearing 55 and a first end cover 56, and the second bearing seat 54 is fixed to the upper part of the lower housing 2 via a second ball bearing 57 and a second end cover 58. The second bevel gear 52 is poweredly connected to a multi-stage gear transmission mechanism. The gear transmission pair includes a meshing first transmission gear 61 and a second transmission gear 62. The first transmission gear 61 is connected to the output end of the reducer 18, and the second transmission gear 62 meshes with the first transmission gear 61 and is mounted via a floating support structure. The floating support structure includes a spring seat 71, several small springs 72, and a flange seat 73. The spring seat 71 is fixed to the inner hole of the upper housing 1, and the several small springs 72 are arranged on the spring seat 71. The flange seat 73 is fixed to the top of the first bevel gear 51. The second transmission gear 62 is fixed to the flange seat 73 and supported by a thrust roller bearing 74, which is supported by several small springs 72. The multi-stage gear transmission mechanism includes a third transmission gear 63, a fourth transmission gear 64, and a fifth transmission gear 65 that mesh sequentially. The third transmission gear 63 is coaxially fixed to the second bevel gear 52. The fourth transmission gear 64 is fixed to the main spindle box 27 by a snap ring 66, a third ball bearing 67, and a third end cap 68. The fourth transmission gear 64 is located below the third transmission gear 63. The fifth transmission gear 65 is fixed to the right end of the main spindle box 27 and is located below the fourth transmission gear 64.

[0031] Multiple stepped holes 11 are provided on the circumference of the bottom of the upper housing 1. Each stepped hole 11 is provided with a 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 33 and the outer side of the first bearing seat 53. 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 33 and the first bearing seat 53. Each pull rod 34 is threaded to the pull sleeve 15. A C-axis loosening oil cavity 37 is formed between the pressure cap 12 and the top end of the pull rod 34. A C-axis clamping oil cavity 36 is formed between the stepped part of the pull rod 34 and the disc spring 35 and the upper end of the sealing cap 14.

[0032] The triple gear assembly includes a positioning gear 91, an indexing gear 92, and a piston gear 93. The positioning gear 91 is fixed to the A-axis bearing housing 41, the indexing gear 92 is mounted on a rotary seat 94, the rotary seat 94 is fixed to the spindle box 27, and the piston gear 93 is axially movable within a transition sleeve 95. The transition sleeve 95 is fixed to the positioning gear 91, and a fourth end cap 96 is fixed on the transition sleeve 95. The A-axis hydraulic cylinder includes an A-axis clamping oil chamber 43, an A-axis releasing oil chamber 44, an A-axis piston 42, and a pull-back seat 45. The piston gear 93 is fixed to the A-axis piston 42, and the pull-back seat 45 is fixed to the indexing gear 92 and moves under hydraulic pressure, so that the piston gear 93 can simultaneously engage or disengage with the positioning gear 91 and the indexing gear 92. The A-axis clamping oil chamber 43 is located between the left side of the fourth end cover 96, the step of the pull-back seat 45, and the right side of the A-axis piston 42. The A-axis release oil chamber 44 is located between the step of the transition sleeve 95 and the outer step of the A-axis piston 42. The spindle box 27 is oscillatingly mounted on the A-axis bearing seat 41 via the fourth ball bearing 38. An oilless bearing 39 is provided between the outer diameter of the right side of the spindle box 27 and the inner hole of the fourth end cover 96. When the triple gear assembly is released, the fourth ball bearing 38 and the oilless bearing 39 jointly bear the radial off-center load of the A-axis.

[0033] 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 releasing 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 releasing positions of the upper gear 31 and the lower gear 32.

[0034] The wiring mechanism includes a first wiring hole 81, a second wiring hole 82, a third wiring hole 83, a fourth wiring hole 84, and a fifth wiring hole 85. The first wiring hole 81 is located on the right side of the spindle box 27. The second wiring hole 82 and the third wiring hole 83 are respectively located on the upper side of the lower housing 2. The fourth wiring hole 84 is located on the top of the lower housing 2. The fifth wiring hole 85 is located below the protective cover 86. The protective cover 86 is located inside the slide ram 19 and is situated at the first bevel gear. Above 51, a terminal block 87 is installed on the upper side of the protective cover 86, and a protective cover 24 is installed on the front side of the lower housing 2. The functional pipeline 30 of the electric spindle 28 is led out from the first wiring hole 81, passes through the space between the spindle housing 27 and the protective cover 24, and converges to the second wiring hole 82 and the third wiring hole 83. Then, it enters the inner hole of the first bevel gear 51 through the fourth wiring hole 84 and then enters the fifth wiring hole 85. Finally, after being organized by the wire fixing plate 88, it is led out from the terminal block 87.

[0035] When the oscillating head needs to perform the C-axis indexing function, the C-axis release oil chamber is filled with oil. Under the action of oil pressure, the pull rod 34 drives the pull sleeve 15 to move downward by a distance L1. The lower gear 32, transition ring 33, lower housing 2, first bevel gear 51, second transmission gear 62, flange seat 73 and other components descend simultaneously by a distance L1 under the action of gravity. After descending, the first transmission gear 61 and the second transmission gear 62 can still be kept in a meshing state. At this time, the upper gear 31 and the lower gear 32 disengage. At the same time, the A-axis clamping oil chamber 43 is filled with oil, and the A-axis oil cylinder drives the triple gear assembly to clamp. After completing the above two steps, the servo motor 17 is powered and provides power to the first transmission gear 61 through the reducer 18. The power is then transmitted to the first bevel gear 51 through the second transmission gear 62 meshing with it, and then to the multi-stage gear transmission mechanism and the triple gear assembly through the second bevel gear 52. Finally, the power is transmitted to the lower housing 2. At this time, the rotation of the A-axis and the second bevel gear 52 is restricted. The servo motor 17 continues to provide indexing power, causing the second bevel gear 52 to perform a large rotation around the center line of the C-axis assembly around the first bevel gear 51. The lower housing 2, the spindle box 27, and the electric spindle 28 move together. After rotating to the required angle, the C-axis clamping oil chamber 36 is filled with oil, and the upper gear 31 meshes with the lower gear 32 to realize the C-axis indexing function (i.e., the oscillating head rotates around the center line of the C-axis assembly).

[0036] When the oscillating head needs to perform the A-axis rotation function, the upper gear 31 and the lower gear 32 mesh, oil enters the A-axis release oil chamber 44, and the A-axis piston 42 drives the piston gear 93 to move to the right. After the three-gear assembly completes the release action, the servo motor 17 transmits power to the multi-stage gear transmission mechanism through the reducer 18, and finally to the spindle box 27, which in turn drives the rotary seat 94, indexing gear 92, pull-back seat 45, electric spindle 28 and other components to rotate around the A-axis together with the spindle box 27. When the rotation reaches an integer multiple of the index of the three-gear assembly, the system performs the clamping action, oil enters the A-axis clamping oil chamber 43, the three-gear assembly clamps, and thus completes the A-axis indexing action (i.e., the electric spindle oscillates around the center line of the A-axis assembly).

Claims

1. A single-pendulum single-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, an A-axis assembly, and a transmission 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. The electric spindle is housed within the spindle box, which has a single-pendulum offset structure. The C-axis drive assembly and the A-axis drive assembly... The components share a single set of servo motor and reducer mounted on the upper housing. The output end of the reducer is connected to a gear transmission pair. The transmission assembly includes a bevel gear pair and a multi-stage gear transmission mechanism. The bevel gear pair is poweredly connected to the gear transmission pair, and the multi-stage gear transmission mechanism is poweredly connected to the bevel gear pair. 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 drive assembly is used to drive the spindle box to swing around the center line of the A-axis assembly. The C-axis positioning assembly includes an upper sprocket, a lower sprocket, and a C-axis positioning mechanism. The C-axis reverse pull mechanism includes an upper sprocket connected to the bottom of the upper housing for centering, and a lower sprocket connected to the top of the lower housing via a transition ring. The C-axis reverse pull mechanism comprises 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, automatically pulling the lower sprocket against the upper sprocket when no external hydraulic pressure is applied. The C-axis clamping oil chamber is used to increase... The pull rod exerts an upward tension on the lower housing, and the C-axis release oil chamber drives the pull rod downward to separate the upper and lower gears. The A-axis positioning assembly includes an A-axis bearing housing, a triple gear assembly, and an A-axis hydraulic cylinder. The A-axis bearing housing is fixed to the lower housing, and the spindle box is swayably mounted on the A-axis bearing housing. The triple gear assembly is disposed between the A-axis bearing housing and the spindle box. The A-axis hydraulic cylinder drives the triple gear assembly to clamp and release. The triple gear assembly is connected to the multi-stage gear transmission mechanism.

2. The single-pendulum single-servo driven 3+2 electric spindle oscillating head according to claim 1, characterized in that, The bevel gear pair includes a first bevel gear and a second bevel gear meshing together. The centerline of the first bevel gear coincides with the centerline of the C-axis assembly, and the centerline of the second bevel gear is parallel to the centerline of the A-axis assembly. The first bevel gear is centered and mounted on the lower housing via a first bearing seat, and the second bevel gear is centered and mounted on the lower housing via a second bearing seat. The first bearing seat is fixed to the upper part of the lower housing via a first ball bearing and a first end cap, and the second bearing seat is fixed to the upper part of the lower housing via a second ball bearing and a second end cap. The second bevel gear is poweredly connected to the multi-stage gear transmission mechanism.

3. The single-pendulum single-servo driven 3+2 electric spindle oscillating head according to claim 2, characterized in that, The gear transmission pair includes a first transmission gear and a second transmission gear that mesh with each other. The first transmission gear is connected to the output end of the 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 first bevel gear. 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. A single pendulum single servo driven 3+2 electric spindle oscillating head according to claim 2, characterized in that, The multi-stage gear transmission mechanism includes a third transmission gear, a fourth transmission gear, and a fifth transmission gear that mesh sequentially. The third transmission gear is coaxially fixed to the second bevel gear. The fourth transmission gear is fixed to the spindle box via a snap ring, a third ball bearing, and a third end cap, and is located below the third transmission gear. The fifth transmission gear is fixed to the right end of the spindle box, and is located below the fourth transmission gear.

5. A single-pendulum single-servo driven 3+2 electric spindle oscillating head according to claim 2, characterized in that, The upper housing has multiple stepped holes on its bottom circumference. Each stepped hole contains a 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 first 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 first bearing seat. Each pull rod is threaded to the pull sleeve. The pressure cap and the top of the pull rod form a 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 a C-axis clamping oil chamber.

6. A single-pendulum single-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 a fourth 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 the positioning gear and the indexing gear.

7. A single-pendulum single-servo driven 3+2 electric spindle oscillating head according to claim 6, 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 fourth 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 transition sleeve step and the outer step of the A-axis piston.

8. A single-pendulum single-servo driven 3+2 electric spindle oscillating head according to claim 6, characterized in that, The spindle box is oscillatingly mounted on the A-axis bearing seat via a fourth 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 fourth end cover. When the triple gear assembly is loosened, the fourth ball bearing and the oilless bearing jointly bear the radial off-center load of the A-axis.

9. A single-pendulum single-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, a fourth wiring hole, and a fifth 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 on the upper side of the lower housing. The fourth wiring hole is located on the top of the lower housing. The fifth wiring hole is located below the protective cover. The protective cover is located inside the slide block and above the bevel gear pair. 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 enter the inner hole of the bevel gear pair through the fourth wiring hole, and then enter the fifth wiring hole. Finally, after being organized by the wire fixing plate, they are led out from the terminal block.

10. A single-pendulum single-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.

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