A thread and gear combined machining machine tool and a machining method thereof

Abstract

The application discloses a thread and gear composite machining machine tool and a machining method thereof, and belongs to the field of composite grinding machining machine tools, and comprises a Z-direction transmission mechanism, an X-direction transmission mechanism and a rotary table assembly rotating around a B shaft, the rotary table is provided with four mounting positions, wherein the first and second main shafts are selected and independently swing around A1 and A2 respectively, and the third and fourth main shafts are selected; a workpiece main shaft is fixed on a Z-direction platform, and a detection device is arranged on the same platform; a grinding wheel dresser swinging around A3 is arranged beside the workpiece main shaft and is fixed in space position with the workpiece main shaft; the rotary table switches any main shaft to a working position facing the workpiece or a dressing position facing the dresser around the B shaft; the dresser position is unchanged, and each main shaft shares the dresser to perform in-situ dressing; the machine tool realizes decoupling control of gear machining and thread grinding through independent swinging of A1 or A2; the composite machining of the tooth part, thread and outer circle of the shaft workpiece can be completed through one-time clamping, and the machine tool is especially suitable for high-precision machining of planetary roller screw rollers, and has compact structure and high precision.

Description

Technical Field

[0001] This invention belongs to the field of composite grinding machine tools, and more specifically, relates to a composite machining machine tool for thread and gear machining and its machining method. Background Technology

[0002] Planetary roller screw pairs are high-precision transmission components that convert rotary motion into linear motion, widely used in aerospace, robotics, precision machine tools, automotive steering systems, and weaponry. The roller, as the core force-transmitting element of the planetary roller screw pair, typically consists of a precision external thread in the middle and external gear rings (or splines) at both ends. During operation, the teeth at both ends mesh with planetary gears or internal gear rings to transmit motion and power, while the central thread engages with a nut to transmit load. Therefore, there is a strict angular positioning requirement between the initial phase of the teeth at both ends of the roller and the initial helix angle of the central thread—if the phase consistency deviation between the teeth and the thread exceeds the allowable range, it will cause meshing interference and uneven load distribution in the planetary roller screw pair, and in severe cases, even jamming or premature failure.

[0003] Currently, the finishing of the teeth and threads on rollers typically employs a sequential machining process. Specifically, the roller teeth are machined on a gear hobbing or gear shaping machine (and for hardened rollers, precision grinding is also required on a gear grinding machine), while the threads are ground on a dedicated thread grinding machine, and the outer diameter is finished on a cylindrical grinding machine. For the thread grinding process itself, rough grinding and finish grinding usually need to be completed on different equipment or in different processes—rough grinding uses multi-spindle grinding wheels to quickly remove excess material, while finish grinding uses single-spindle grinding wheels to ensure final accuracy. However, multi-spindle and single-spindle grinding wheels have different requirements for spindle rigidity, cooling conditions, and process parameters, making it difficult to achieve both on the same spindle using traditional equipment. Therefore, rough grinding and finish grinding often need to be performed sequentially. This means that the same roller workpiece must undergo at least multiple specialized machines and multiple clamping operations to complete the finishing of all its features. Taking thread grinding as an example, when the workpiece is clamped on the thread grinding machine, it is positioned by the center holes at both ends. After grinding, it needs to be disassembled and transferred to a gear hobbing machine, re-clamped, aligned, indexed, and then the teeth are machined again. Each time it is re-clamped, the positioning datum changes, which not only introduces repeated positioning errors but also makes it difficult to accurately guarantee the phase relationship between the teeth and the thread. For planetary roller screw pairs, this phase error is fatal.

[0004] In addition, sequential processing also brings the following problems:

[0005] (1) Low production efficiency and long production cycle: The workpiece is repeatedly loaded, unloaded, transferred, and aligned between gear hobbing machines, gear grinding machines, thread grinding machines, and cylindrical grinding machines, and the auxiliary time is much longer than the actual cutting time. In particular, the sequential processing of rough grinding and fine grinding of threads further increases the number of times the workpiece is transferred and re-clamped between different machines. For mass-produced roller parts, this process route is extremely inefficient and cannot meet the needs of large-scale mass production.

[0006] (2) High equipment investment costs: Gear hobbing machines, gear grinding machines, thread grinding machines, and cylindrical grinding machines are all high-precision special equipment. The price of a single imported machine is usually several million RMB, and the total investment for multiple machines exceeds ten million RMB, which poses a very high capital threshold for small and medium-sized manufacturing enterprises. At the same time, multiple machines occupy a large workshop area, increasing the investment in factory buildings and infrastructure.

[0007] (3) Thin-walled or slender rollers are prone to deformation during multiple clamping: Rollers are usually slender shaft parts. During multiple clamping processes, the clamping force is repeatedly applied to the workpiece surface, which can easily lead to damage to the machined surface or bending deformation of the workpiece, making it difficult to guarantee the yield rate.

[0008] (4) It is difficult to achieve high precision coaxiality and phase synchronization between the teeth and the thread: The roller teeth and the thread need to ensure extremely high coaxiality (usually required to be ≤0.005mm) and strict angular phase relationship (phase deviation is usually required to be ≤±30 minutes). The cumulative positioning error caused by multiple clamping cannot meet the above precision requirements, which limits the improvement of the overall performance of the planetary roller screw pair.

[0009] To address the aforementioned issues, some composite machining tools have been attempted in the existing technology. For example, one solution uses a pair of head and tailstocks to clamp both ends of a shaft-like part and drives the head and tailstocks to move away from or closer to each other axially, allowing the part to undergo external thread grinding and gear hobbing under axial tension. This solution mainly addresses the problem of instability and deformation that easily occurs in slender shaft-like parts during axial clamping machining, but it still has the following shortcomings: First, its gear hobbing mechanism can only perform gear hobbing and cannot perform fine grinding of hardened gears; second, the external thread grinding mechanism and gear hobbing mechanism are switched by rotating the tool holder around the vertical axis, and all mechanisms share the same rotation axis, making it impossible to achieve independent adjustment of the angles required for gear machining and thread machining; third, it does not address the issue of the coordinated operation of rough and fine thread grinding.

[0010] Another approach uses a Z-axis moving mechanism with a headstock and tailstock to hold the workpiece in place. The X-axis moving mechanism is connected to the Y-axis moving mechanism via a column. The Y-axis is connected to the A-axis rotating mechanism, which integrates grinding heads arranged in a staggered pattern in four directions (up, down, left, and right). This approach achieves combined grinding of teeth and threads, but it still has the following drawbacks: all four grinding heads are integrated on the same A-axis rotating mechanism, sharing the same rotation axis. The relative angles between the grinding heads are fixed, making it impossible to independently adjust the different angles required for teeth and threads, thus limiting its applicability in complex machining scenarios with different combinations of helix angles / rise angles.

[0011] In addition, none of the above-mentioned existing composite machining tool solutions involve the integration of the following key functional modules: (1) a center frame that provides intermediate auxiliary support for slender shaft workpieces during the machining process - for planetary roller screw rollers with a large length-to-diameter ratio, the lack of intermediate support will cause the workpiece to bend and deform under the action of grinding force, directly affecting the coaxiality accuracy of the teeth and threads; (2) a measuring device for in-situ detection of the workpiece before and after machining - the lack of in-machine detection means that if the machining accuracy needs to be verified, the workpiece must be unloaded and moved to the detection equipment, which destroys the process continuity of "one-time clamping"; (3) a grinding wheel dresser that can serve multiple different spindles and its position definition in the machine tool coordinate system - as an essential component of the grinding machine, the spatial position and kinematic definition of the dresser are the basic information for those skilled in the art to understand and implement composite machining tool solutions.

[0012] Furthermore, none of the aforementioned existing composite machining center solutions define the spatial position of the grinding wheel dresser in the machine tool coordinate system. Specifically, in composite machining center solutions integrating multiple grinding heads or machining mechanisms, the dresser (if any) can only move with the grinding wheel head or rotary mechanism, and cannot establish an independent and fixed spatial position in the machine tool coordinate system; the various machining mechanisms switch through the rotation of the tool carriage or rotary axis, and similarly, the independent spatial position of the dresser is not defined. As an essential component of a grinding machine, the spatial position and kinematic definition of the dresser are fundamental information for the composite machining center to achieve the "one-time setup, all-round completion" function. The uncertainty of the dresser's position in the above solutions makes it impossible for those skilled in the art to determine the spatial relationship between its dressing datum and machining datum, and also makes it impossible to achieve composite dressing where different spindles share the same dresser.

[0013] The aforementioned technical challenges have not yet been effectively resolved in existing composite machining tools. Summary of the Invention

[0014] The main objective of this invention is to provide a machine tool for combined thread and gear machining and its machining method, in order to solve the technical problems mentioned in the background art, such as the difficulty in synchronizing the phase of the teeth and threads, the difficulty in combining rough and fine grinding on the same equipment, the low efficiency of multiple clamping, and the lack of a systematic dressing-measurement-support process closed loop.

[0015] According to a first aspect of the present invention, a thread and gear composite machining machine tool is provided, including a bed, on which a Z-axis transmission mechanism and an X-axis transmission mechanism are provided. A turntable assembly is rotatably mounted on the X-axis transmission mechanism. A first tilting mechanism and a second tilting mechanism are provided on the turntable assembly. A first spindle is movably mounted on the first tilting mechanism, and a second spindle is mounted on the second tilting mechanism. The first tilting mechanism and the second tilting mechanism are located on opposite sides of the turntable assembly and are rotatably mounted about mutually independent axes A1 and A2, respectively. A workpiece spindle is provided on the Z-axis transmission mechanism.

[0016] A dresser swing angle device is fixedly installed on the side of the workpiece spindle near the X-axis transmission mechanism. A grinding wheel dresser is rotatably mounted on the dresser swing angle device. The grinding wheel dresser swings independently around the A3 axis. The grinding wheel dresser has a fixed spatial position relationship with the workpiece spindle in the machine tool coordinate system. The grinding wheel dresser is located between the workpiece spindle and the rotary table assembly.

[0017] The Z-axis transmission mechanism is equipped with a detection device, which is mounted on the same mounting platform as the workpiece spindle. The two are linked together with the Z-axis transmission mechanism along the Z-axis direction. The detection device is used to perform in-situ detection of the workpiece and / or the processed part.

[0018] The turntable assembly has four mounting positions, wherein:

[0019] The first mounting position is provided with the first swing angle mechanism and the first spindle. The first spindle is a gear machining spindle, which is used to mount gear hobbing cutters or gear machining grinding wheels to realize gear hobbing or gear grinding of the workpiece.

[0020] The second mounting position is provided with the second swing angle mechanism and the second spindle. The second spindle is a thread finishing spindle, which is used to mount a thread grinding wheel to achieve thread finishing of the workpiece.

[0021] The third mounting position is the first optional mounting position, which is used to selectively install the third spindle or leave it empty. The third spindle is an external cylindrical grinding spindle, which is used to install an external cylindrical grinding wheel to realize the external cylindrical grinding of the workpiece.

[0022] The fourth mounting position is the second optional mounting position, which is used to selectively install the fourth spindle or leave it empty. The fourth spindle is a thread roughing spindle, which is used to install a multi-wire grinding wheel to achieve rough grinding of the workpiece thread.

[0023] The first and second spindles are mandatory, while the third and fourth spindles are optional. The rotary table assembly rotates around the B-axis, allowing the spindle in any mounting position to selectively switch to either a working position facing the workpiece spindle or a dressing position facing the grinding wheel dresser. The grinding wheel dresser maintains a constant spatial position in the machine tool coordinate system. Each spindle switches to the dressing position via the rotation of the rotary table assembly around the B-axis, enabling grinding wheels on different spindles to share the same grinding wheel dresser for in-situ dressing.

[0024] According to a first aspect embodiment of the present invention, the thread and gear composite machining machine tool includes a dresser swing angle device comprising a dresser swing angle body, a dresser swing angle shaft, and a dresser swing angle rotating plate. The dresser swing angle body is fixedly disposed on the side of the workpiece spindle near the X-axis transmission mechanism. One end of the dresser swing angle shaft is rotatably connected to the dresser swing angle body, and the other end of the dresser swing angle shaft is fixedly connected to the dresser swing angle rotating plate. The grinding wheel dresser is fixedly disposed on the dresser swing angle rotating plate. An angle encoder is disposed on the dresser swing angle shaft for detecting the swing angle of the dresser swing angle rotating plate around the A3 axis. The angle encoder is communicatively connected to the CNC system of the machine tool to achieve precise closed-loop control of the dressing angle. The dresser swing angle device is further provided with a locking mechanism for locking the dresser swing angle rotating plate and the dresser swing angle body after the grinding wheel dresser swings to the target angle, so as to maintain the stability of the dressing posture.

[0025] According to the first aspect of the present invention, the thread and gear composite machining machine tool is provided with a center frame on the Z-axis transmission mechanism. The center frame and the workpiece spindle are mounted on the same mounting platform, and the two are linked together with the Z-axis transmission mechanism along the Z-axis direction. The center frame is used to provide auxiliary support for the outer circle of the workpiece.

[0026] According to the first aspect of the present invention, the thread and gear composite machining tool is used for initial position tool setting and / or machining accuracy detection of the workpiece.

[0027] According to a first aspect embodiment of the present invention, the thread and gear composite machining machine tool, the detection device includes a probe or probe head, which is communicatively connected to the CNC system of the machine tool.

[0028] According to the first aspect of the present invention, the thread and gear composite machining machine tool realizes gear hobbing when the first spindle is equipped with a hobbing cutter, realizes worm gear grinding when the first spindle is equipped with a worm grinding wheel, and realizes profile grinding when the profile grinding wheel is equipped with a profile grinding wheel.

[0029] According to the first aspect of the present invention, in the thread and gear composite machining machine tool, the second spindle is equipped with a thread grinding wheel for thread grinding of the workpiece.

[0030] According to the first aspect of the present invention, the thread and gear composite machining machine tool is provided with a third spindle equipped with an external cylindrical grinding wheel for external cylindrical grinding of the workpiece.

[0031] According to the first aspect of the present invention, the thread and gear composite machining machine tool is provided with a fourth spindle equipped with a multi-line grinding wheel. The outer circumferential surface of the multi-line grinding wheel is provided with a plurality of annular grinding teeth, each annular grinding tooth being arranged along the axial direction of the grinding wheel, so that multiple helical lines of the thread are ground simultaneously in one pass.

[0032] According to the first aspect of the present invention, the thread and gear composite machining machine tool includes a rotary table, a mounting column and a rotary table drive device. The mounting column is fixedly disposed on the rotary table and has four mounting surfaces corresponding to the four mounting positions. The rotary table drive device is connected to the rotary table to drive the rotary table to rotate around the B-axis.

[0033] According to the first aspect of the present invention, the thread and gear composite machining machine tool has an inspection port at the top of the mounting column.

[0034] According to a first aspect embodiment of the present invention, the thread and gear composite machining machine tool includes a first swing angle mechanism comprising a first swing angle body, a first swing angle shaft, and a first swing angle rotating plate. A Y-axis transmission mechanism is provided on the first swing angle rotating plate. The first swing angle body is rotatably connected to the first swing angle rotating plate via the first swing angle shaft. The first swing angle body is disposed on one side of the turntable assembly. The Y-axis transmission mechanism feeds along the axial direction of the first spindle, and the Y-axis changes direction as the first swing angle mechanism swings around the A1 axis.

[0035] According to the first aspect of the present invention, the thread and gear composite machining machine tool includes a Y-axis transmission mechanism comprising a Y-axis guide rail, a Y-axis slide plate, and a Y-axis drive device. The Y-axis guide rail is disposed on the first swing angle rotating plate, the first spindle is fixedly mounted on the Y-axis slide plate, and the Y-axis drive device is disposed at the rear end of the first swing angle rotating plate and drives the Y-axis slide plate to move back and forth along the length direction of the Y-axis guide rail.

[0036] According to the first aspect of the present invention, the thread and gear composite machining machine tool includes a second swing angle mechanism, a second swing angle shaft, and a second swing angle rotating plate. The second spindle is fixedly mounted on the second swing angle rotating plate. The second swing angle body is disposed on the side of the turntable assembly away from the first swing angle mechanism. The second swing angle body is rotatably connected to the second swing angle rotating plate through the second swing angle shaft.

[0037] According to the first aspect of the present invention, in the thread and gear composite machining machine tool, two to three diamond rollers can be installed on the spindle of the grinding wheel dresser, namely a first diamond roller, a second diamond roller and a third diamond roller, and each diamond roller is selected and installed according to the dressing requirements; wherein, the first diamond roller is used to dress worm grinding wheels and multi-line grinding wheels, and the second diamond roller is used to dress external thread grinding wheels and external cylindrical grinding wheels.

[0038] According to the first aspect of the present invention, the thread and gear composite machining machine tool may optionally be provided with a tailstock on the Z-axis transmission mechanism. The tailstock is coaxially opposite to the workpiece spindle and is used to assist in clamping the workpiece.

[0039] According to the first aspect of the present invention, the thread and gear composite machining machine tool, the X-axis, Z-axis, C-axis, A1-axis, A2-axis, B-axis, Y-axis, A3-axis, B1-axis and W-axis of the machine tool are all controlled by a fully closed loop.

[0040] According to a second aspect of the present invention, a machining method for a thread and gear composite machining tool is provided, which uses the aforementioned thread and gear composite machining tool for machining, and includes the following steps:

[0041] S1: The shaft-type workpiece to be processed is clamped between the workpiece spindle and the tailstock in one go, and the workpiece is driven to rotate around the C-axis by the workpiece spindle;

[0042] S2: The required spindle is switched to the working position by moving the X-axis transmission mechanism and / or the Z-axis transmission mechanism, and by rotating the turntable assembly around the B-axis;

[0043] S2-1: When the gear-cutting grinding wheel mounted on the first spindle or the thread-grinding grinding wheel mounted on the second spindle needs dressing, the corresponding spindle is switched to the dressing position facing the grinding wheel dresser by rotating the turntable assembly around the B-axis. The grinding wheel dresser maintains a constant spatial position in the machine tool coordinate system. After the corresponding spindle rotates to the dressing position via the B-axis, it forms a dressing engagement relationship with the grinding wheel dresser. The grinding wheel dresser swings around the A3-axis to adjust the corresponding diamond roller mounted on its spindle to the dressing posture, performing in-situ dressing of the grinding wheel. After dressing is completed, the corresponding spindle is switched back to the working position by rotating the turntable assembly around the B-axis to continue machining.

[0044] S3: When performing tooth machining, the first spindle is switched to the working position by rotating the turntable assembly around the B axis. The first spindle is driven to swing around the A1 axis by the first swing angle mechanism to adjust the angle between the hobbing cutter or tooth profile machining wheel on the first spindle and the workpiece axis so as to match the helix angle or entry angle of the tooth to be machined. Then the first spindle is started to perform hobbing or tooth grinding on the workpiece teeth.

[0045] S4: When performing thread finishing, the second spindle is switched to the working position by rotating the turntable assembly around the B axis. The second spindle is driven to swing around the A2 axis by the second swing angle mechanism to adjust the angle between the thread grinding wheel on the second spindle and the workpiece axis so as to match the helix angle of the thread to be processed. Then the second spindle is started to perform thread finishing on the workpiece.

[0046] When the third spindle is installed in the third mounting position, the processing method further includes step S5: switching the third spindle to the working position by rotating the turntable assembly around the B axis, and starting the external cylindrical grinding wheel on the third spindle to perform external cylindrical grinding on the workpiece;

[0047] When the fourth spindle is installed in the fourth mounting position, the processing method further includes step S6: before step S4, the fourth spindle is switched to the working position by rotating the turntable assembly around the B axis, and the multi-line grinding wheel on the fourth spindle is started to rotate, so that the multi-line grinding wheel can grind multiple spiral lines of the thread simultaneously in one pass.

[0048] The A1 axis and the A2 axis are independent swing axes; wherein, step S6 must be executed before step S4, and the execution order of steps S3, S4 and S5 can be interchanged according to the workstation configuration and processing requirements.

[0049] According to the machining method of the thread and gear composite machining machine tool according to the second aspect embodiment of the present invention, when the third mounting position and the fourth mounting position are respectively mounted on the third spindle and the fourth spindle, step S6 must be performed before step S4, and the order of steps S3, S4 and S5 can be adjusted according to machining requirements.

[0050] The machining method of the thread and gear composite machining machine tool according to the second aspect embodiment of the present invention further includes step S0: before step S3 and / or S4, the workpiece is initially positioned by the detection device to determine the initial position of the workpiece in the machine tool coordinate system.

[0051] The machining method of the thread and gear composite machining machine tool according to the second aspect embodiment of the present invention further includes step S7: after steps S3, S4, S5 and / or S6, the machined part is inspected by the detection device to obtain machining accuracy data.

[0052] One of the above-described technical solutions of the present invention has at least one of the following advantages or beneficial effects:

[0053] (1) This invention integrates the first independent tilting mechanism (A1 axis) and the second independent tilting mechanism (A2 axis) onto the B-axis rotary table, achieving fully decoupled independent angle control for gear machining (gear hobbing / worm gear grinding / form grinding of helical gears) and thread grinding, breaking through the limitation of existing composite machine tools where multiple spindles share a single rotary axis and the angle cannot be adjusted independently. This difference allows this invention to select the optimal machining angle for helical gears with different helix angles and threads with different helix angles, achieving the best machining effect for each while ensuring phase synchronization accuracy.

[0054] (2) This invention achieves modular combination of machine tool functions by arranging four spindles on the four mounting surfaces of the rotary table assembly, and specifying that the gear machining spindle (capable of gear hobbing) and the thread finishing spindle are core mandatory configurations, while the external cylindrical grinding spindle and the thread roughing spindle are optional configurations. Users can select different functional configurations according to specific processing needs, effectively controlling equipment costs while ensuring core functions, and taking into account both versatility and economy.

[0055] (3) This invention integrates four functions—gear hobbing, gear grinding, thread grinding (including multi-line rough grinding and single-line fine grinding) and external cylindrical grinding—into one machine tool, enabling the planetary roller screw roller to complete all feature processing in one clamping. This eliminates the phase accumulation error caused by repeated positioning in sequential processing from the root, ensuring that the coaxiality between the roller teeth and the thread is ≤0.005mm and the phase deviation is ≤±30 minutes.

[0056] (4) This invention integrates a multi-line grinding wheel on the fourth spindle, which works in conjunction with a single-line fine grinding wheel on the second spindle to achieve continuous completion of thread roughing and fine grinding on the same machine tool and in the same clamping. The multi-line grinding wheel simultaneously rough grinds multiple helical lines of the thread in one pass, which can quickly remove most of the excess material and greatly improve the roughing efficiency; the single-line grinding wheel then performs fine grinding to ensure micron-level dimensional accuracy and ideal surface quality. Roughing and fine grinding are driven by independent spindles, and each can select the optimal grinding wheel linear speed, cooling method and grinding parameters, fundamentally solving the process contradiction that a single spindle cannot balance roughing efficiency and fine grinding accuracy.

[0057] (5) The B-axis turntable enables rapid switching between different spindles, eliminating the time for workpiece transfer, alignment and repeated clamping between multiple machines, which can greatly improve production efficiency and reduce equipment investment and workshop area occupation.

[0058] (6) Since the A1 axis and A2 axis can be independently and steplessly adjusted, the present invention can adapt to the combination of helical gear machining with different helix angles and thread grinding with different helix angles, covering a variety of specifications and models of planetary roller screw rollers, and has good versatility and flexibility.

[0059] (7) By setting a detection device on the Z-axis transmission mechanism and placing it on the same mounting platform as the workpiece spindle, the workpiece can be initially positioned before processing and the processing part can be in-situ accuracy detected after processing, which further improves the level of processing automation and dimensional accuracy control capability, without having to unload the workpiece and move it to the detection equipment.

[0060] (8) By setting a center frame on the Z-axis transmission mechanism and placing it on the same mounting platform as the workpiece spindle, intermediate auxiliary support can be provided for slender shaft workpieces during processing, thereby enhancing workpiece rigidity, reducing bending deformation caused by cutting force, and further improving processing accuracy.

[0061] (9) Tailstock (6) is an optional configuration. When the workpiece is a slender or thin-walled shaft, a tailstock can be installed to enhance clamping stability. For short and thick workpieces that do not require auxiliary clamping, the tailstock can be left empty, further improving the configuration flexibility and applicability of the machine tool.

[0062] (10) This invention places the grinding wheel dresser on the workpiece spindle side and equips it with an independent A3 swing axis, giving the dresser an independent coordinate definition in the machine tool coordinate system. The dresser establishes a fixed spatial binding relationship with the workpiece spindle (C-axis), unifying the dressing datum with the machining datum, resulting in a short precision chain and small error accumulation. The dresser can actively swing along the A3 axis to align with the grinding wheels at four different mounting positions on the rotary table assembly, achieving composite dressing of "one dresser dressing multiple wheels". The spatial positional relationship between the dresser on the workpiece spindle side and the B-axis rotary table allows the spindle at any mounting position to switch to the dressing position facing the dresser via the B-axis rotation, forming a "machining position - dressing position" dual-station switching logic. After dressing, the grinding wheel can continue machining without disassembly, significantly improving the automation level of the entire machine.

[0063] (11) In this invention, the center frame and the detection device are mounted on the same Z-axis slide plate as the workpiece spindle. The three components move in tandem with the Z-axis and maintain a fixed spatial relationship relative to the axial position of the workpiece. During the machining process, the center frame provides intermediate auxiliary support for slender shaft-type workpieces, enhancing rigidity and reducing bending deformation, thus ensuring a phase synchronization accuracy of coaxiality ≤0.005mm. The detection device completes tool setting and positioning (S0) and accuracy verification (S7) before and after machining, respectively, allowing for full-process inspection without disassembling the workpiece. Together with the workpiece spindle, the three components form a complete closed-loop process of "clamping-supporting-machining-inspection," making the technical effect of "one-time clamping, all completed" fully feasible in engineering.

[0064] (12) In this invention, the grinding wheel dresser is defined as an independent node with a fixed spatial position in the machine tool coordinate system, forming a system-level collaboration with the "dressing position" switching logic of the B-axis rotary table. The dresser does not move with any sliding components or swinging mechanisms and maintains an absolute position unchanged in the machine tool coordinate system; each spindle reaches the dressing position one by one through the rotation of the B-axis to complete the dressing. This dressing logic of "dresser fixed, spindle in position" enables one dresser to serve grinding wheels in four different mounting positions, realizing the comprehensive integration of the dressing process, while simplifying the control logic of the dressing motion - during dressing, only the swing of the A3 axis needs to be controlled to adjust the attitude of the diamond roller, without the need for complex spatial coordinate conversion. In addition, the angle encoder and locking mechanism set on the dresser swing angle device ensure the precise closed-loop control of the dressing angle and the stable maintenance of the dressing attitude, further ensuring the dressing accuracy and repeatability accuracy. Attached Figure Description

[0065] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0066] Figure 1 These are schematic diagrams of the structure of a thread and gear composite machining center in some embodiments of the present invention;

[0067] Figure 2This is a schematic diagram of the thread and gear composite machining tool from another perspective in some embodiments of the present invention;

[0068] Figure 3 This is a schematic diagram of the structure of the grinding wheel dresser in some embodiments of the present invention;

[0069] Figure 4 This is a partially enlarged schematic diagram of the grinding wheel dresser in some embodiments of the present invention.

[0070] Attached image labels:

[0071] 1-Bed; 2-Z-axis transmission mechanism; 3-X-axis transmission mechanism; 31-X-axis slide plate; 4-Workpiece spindle; 5-Turntable assembly; 51-Turntable; 52-Mounting column; 521-Mounting surface; 522-Inspection port; 6-Tailstock; 7-Grinding wheel dresser; 7a-First diamond roller; 7b-Second diamond roller; 71-Dresser swing angle device; 8-Third spindle; 9-First swing angle mechanism; 91-First swing angle body; 92-First swing angle rotating plate; 93-Y-guide rail; 94-Y-axis slide plate; 95-Y-axis drive device; 11-First spindle; 12-Second swing angle mechanism; 121-Second swing angle body; 122-Second swing angle rotating plate; 13-Second spindle; 14-Fourth spindle; 15-Detection device; 16-Center rest.

[0072] Axis labeling: X-axis (X-direction transmission mechanism 3 feed direction), Z-axis (Z-direction transmission mechanism 2 feed direction), Y-axis (Y-direction transmission mechanism feed direction), C-axis (workpiece spindle 4 rotary axis), B-axis (turntable assembly 5 rotary axis), A1-axis (first swing angle mechanism 9 swing axis), A2-axis (second swing angle mechanism 12 swing axis), A3-axis (grinding wheel dresser 7 swing axis), B1-axis (first spindle 11 rotation axis), W-axis (second spindle 13 axial feed axis). Detailed Implementation

[0073] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0074] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0075] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" and "second" may explicitly or implicitly include one or more features.

[0077] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection or a connection that allows communication between the two components; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components, an indirect connection, or an interaction between two components.

[0078] The following disclosure provides many different implementations or examples for different ways of implementing the present invention.

[0079] It should be noted that the Y-axis transmission mechanism defined in this invention is mounted on the first swing angle rotating plate 92, and its feed direction is along the axial direction of the first spindle 11. Furthermore, the spatial direction of the Y-axis changes with the swing of the first swing angle mechanism 9 around the A1 axis. Therefore, the Y-axis of this invention differs from the fixed-direction Y-axis in traditional CNC machine tools; it is a linear motion axis that changes direction following the swing of the A1 axis. Those skilled in the art should understand this to be accurate.

[0080] Example 1 (Equipment Structure Example)

[0081] like Figure 1 , Figure 2 As shown, the present invention provides a thread and gear composite machining machine tool, including a bed 1. The bed 1 adopts a flat bed structure, and a Z-axis transmission mechanism 2 and an X-axis transmission mechanism 3 are arranged on the bed 1.

[0082] The Z-axis transmission mechanism 2 includes a Z-axis slide plate, a Z-axis slide rail, and a Z-axis drive device. The Z-axis slide rail is mounted on the bed 1, and the Z-axis slide plate is movably mounted on the Z-axis slide rail. The Z-axis drive device drives the Z-axis slide plate to move back and forth along the Z-axis. The workpiece spindle 4 is fixedly mounted on the Z-axis slide plate. The workpiece spindle 4 is a C-axis rotary spindle used to clamp and drive the workpiece to rotate. A tailstock 6 can also be optionally mounted on the Z-axis slide plate. When the workpiece is a slender or thin-walled shaft-like part, a tailstock 6 can be installed. The tailstock 6 is coaxially opposite to the workpiece spindle 4 and is used to assist in clamping the workpiece and enhance clamping stability. For short and thick workpieces that do not require auxiliary clamping, this mounting position can be left empty.

[0083] A center rest 16 is also installed on the Z-axis slide plate, and the center rest 16 and the workpiece spindle 4 are mounted on the same platform. The center rest 16 is used to provide auxiliary support for the outer diameter of the workpiece, providing intermediate support for slender shaft-like workpieces during machining, enhancing workpiece rigidity, reducing bending deformation caused by cutting forces, and further improving machining accuracy. The center rest 16 can adopt a manual or automatic centering structure, and its position along the Z-axis can be adjusted according to the workpiece length and support requirements. Because the center rest 16 is set on the Z-axis slide plate and moves in conjunction with the workpiece spindle 4 along the Z-axis, it can provide intermediate auxiliary support for the workpiece at any Z-axis position, breaking through the limitation of traditional fixed center rests that can only support workpieces of a specific length.

[0084] A detection device 15 is also installed on the Z-axis slide, and the detection device 15 and the workpiece spindle 4 are mounted on the same platform. The detection device 15 includes a probe or probe head, which is communicatively connected to the CNC system of the machine tool. The detection device 15 is used to perform initial position setting of the workpiece before machining to determine the initial position of the workpiece in the machine tool coordinate system; it is also used to perform in-situ detection of the machined parts after machining to obtain machining accuracy data. Since the detection device 15 is installed on the Z-axis slide, it can move with the Z-axis to any position along the workpiece axis to detect different machined parts such as teeth, threads, and outer diameters. The detection datum and the machining datum are unified (both are in the C-axis coordinate system of the workpiece spindle), and the entire process of detection can be completed without disassembling the workpiece.

[0085] The X-axis transmission mechanism 3 includes an X-axis slide plate 31, an X-axis slide rail, and an X-axis drive device. The X-axis slide rail is mounted on the bed 1, the X-axis slide plate 31 is movably mounted on the X-axis slide rail, and the X-axis drive device is used to drive the X-axis slide plate 31 to move back and forth along the X-axis direction. The turntable assembly 5 is fixedly mounted on the X-axis slide plate 31.

[0086] The turntable assembly 5 includes a turntable 51, a mounting column 52, and a turntable drive device. The mounting column 52 is fixedly mounted on the turntable 51, and has four mounting surfaces 521. In this embodiment, the four mounting surfaces are arranged as follows:

[0087] The first mounting surface is provided with the first swing angle mechanism 9 and a first spindle 11 mounted thereon. The first spindle 11 is a gear machining spindle used to mount hobbing cutters, worm gear grinding wheels, or profile grinding wheels to respectively achieve hobbing, worm gear grinding, or profile gear grinding. The first swing angle mechanism 9 can drive the first spindle 11 to swing around axis A1 to precisely adjust the angle between the hobbing cutter or grinding wheel and the workpiece axis, matching the helix angle or entry angle of the tooth to be machined. The first spindle 11 itself rotates around its axis, which is defined as axis B1 in this invention, and precise speed and angle control is achieved through a servo motor and angle encoder.

[0088] The second mounting surface is equipped with the second swing angle mechanism 12 and a second spindle 13 mounted thereon. The second spindle 13 is a thread finishing spindle used to mount a thread grinding wheel for thread finishing of the workpiece. The second swing angle mechanism 12 can drive the second spindle 13 to swing around the A2 axis to precisely adjust the angle between the grinding wheel and the workpiece axis, matching the helix angle of the thread to be processed. The second spindle 13 is equipped with a W-axis feed mechanism, which drives the thread grinding wheel mounted on the second spindle 13 to feed along its own axis, achieving axial feed motion during thread grinding. Simultaneously, the W-axis feed mechanism is also used to align the grinding wheel before thread grinding. The operator can manually input coordinate values ​​through the touch panel of the CNC system or precisely control the movement of the W-axis by turning the handwheel, ensuring that the working surface of the thread grinding wheel precisely coincides with the rotation center of the A2 axis, thus preventing the grinding wheel from shifting its working position when swinging around the A2 axis to adjust the helix angle. The W-axis is an independently controllable linear feed axis, which achieves precise position control through a servo motor and position detection element. Its feed position is set by the CNC system through touch input or automatic tool setting program.

[0089] The third mounting surface is the first optional mounting position, used for selectively mounting the third spindle 8 or leaving it empty. The third spindle 8 is an external cylindrical grinding spindle, used to mount an external cylindrical grinding wheel for external cylindrical grinding of the workpiece. The third spindle 8 is mounted on the mounting column 52, located between the first swing angle mechanism 9 and the second swing angle mechanism 12.

[0090] The fourth mounting surface is the second optional mounting position, used for selectively mounting the fourth spindle 14 or leaving it empty. The fourth spindle 14 is a thread roughing spindle, used to mount a multi-spindle grinding wheel to achieve rough grinding of the workpiece thread. The outer circumferential surface of the multi-spindle grinding wheel is provided with multiple annular grinding teeth, each annular grinding tooth arranged along the grinding wheel axis, simultaneously grinding multiple helical lines of the thread in one pass, which can quickly remove most of the thread allowance and significantly improve rough grinding efficiency.

[0091] Among them, the first spindle 11 and the second spindle 13 are core mandatory functional modules, while the third spindle 8 and the fourth spindle 14 are optional functional modules, which can be installed one or both according to processing requirements.

[0092] The turntable drive device is connected to the turntable 51 to drive the turntable 51 to rotate around the B axis, thereby selectively switching either of the above spindles to the working position facing the workpiece spindle 4, or to the dressing position facing the grinding wheel dresser 7, forming a "machining position-dressing position" dual-station switching logic.

[0093] It should be noted that, since the third spindle 8 and the fourth spindle 14 are optional configurations and are fixedly installed on the corresponding mounting surfaces of the mounting column 52, they do not have independent tilting mechanisms. When external cylindrical grinding or rough thread grinding is required, the machining feed and angle control are achieved by the linkage of the X-axis transmission mechanism 3 and the Z-axis transmission mechanism 2.

[0094] The first swing angle mechanism 9 includes a first swing angle body 91, a first swing angle shaft, and a first swing angle rotating plate 92. The first swing angle body 91 is fixedly mounted on one side of the turntable assembly 5. The first swing angle body 91 is rotatably connected to the first swing angle rotating plate 92 via the first swing angle shaft, allowing the first swing angle rotating plate 92 to swing around axis A1. A Y-axis transmission mechanism is provided on the first swing angle rotating plate 92. The Y-axis transmission mechanism includes a Y-axis guide rail 93, a Y-axis slide plate 94, and a Y-axis drive device 95. The Y-axis guide rail 93 is mounted on the first swing angle rotating plate 92, the first main shaft 11 is fixedly mounted on the Y-axis slide plate 94, and the Y-axis drive device 95 is located at the rear end of the first swing angle rotating plate 92 and drives the Y-axis slide plate 94 to move back and forth along the length direction of the Y-axis guide rail 93.

[0095] The second swing angle mechanism 12 includes a second swing angle body 121, a second swing angle shaft, and a second swing angle rotating plate 122. The second swing angle body 121 is fixedly disposed on the side of the turntable assembly 5 away from the first swing angle mechanism 9. The second swing angle body 121 is rotatably connected to the second swing angle rotating plate 122 via the second swing angle shaft, allowing the second swing angle rotating plate 122 to swing around axis A2. The second main shaft 13 is fixedly mounted on the second swing angle rotating plate 122.

[0096] A dresser swing angle device 71 is fixedly installed on the side of the workpiece spindle 4 near the X-axis transmission mechanism 3. The workpiece spindle 4 is connected to the grinding wheel dresser 7 through the dresser swing angle device 71. The dresser swing angle device 71 includes a dresser swing angle body, a dresser swing angle shaft, and a dresser swing angle rotating plate. The dresser swing angle body is fixedly installed on the side of the workpiece spindle 4 near the X-axis transmission mechanism 3. One end of the dresser swing angle shaft is rotatably connected to the dresser swing angle body, and the other end of the dresser swing angle shaft is fixedly connected to the dresser swing angle rotating plate. The grinding wheel dresser 7 is fixedly installed on the dresser swing angle rotating plate. An angle encoder is installed on the dresser swing angle shaft to detect the swing angle of the dresser swing angle rotating plate around the A3 axis. The angle encoder is communicatively connected to the CNC system of the machine tool to achieve precise closed-loop control of the dressing angle. The dresser swing angle device 71 is also equipped with a locking mechanism. When the grinding wheel dresser 7 swings to the target angle, the locking mechanism locks the dresser swing angle rotating plate and the dresser swing angle body to maintain the stability of the dressing posture and prevent posture deviation caused by vibration or external force during the dressing process. The dresser swing angle body is rotatably connected to the dresser swing angle rotating plate through the dresser swing angle shaft to drive the grinding wheel dresser 7 to swing independently around the A3 axis. The grinding wheel dresser 7 is located between the workpiece spindle 4 and the rotary table assembly 5, and has an independent and fixed spatial position definition in the machine tool coordinate system—the dresser does not move with any sliding components or swing mechanism, and maintains an absolute position unchanged in the machine tool coordinate system. The A3 axis is an independently controllable swing axis, which can achieve precise swing positioning of the grinding wheel dresser 7 through CNC system control to meet the dressing requirements of grinding wheels with different profiles. The dresser actively swings along the A3 axis, aligning itself with four different mounting positions on the turntable assembly 5 to achieve composite dressing of "one dresser dressing multiple wheels". After the B-axis turntable switches the spindle to be dressed to the dressing position facing the dresser, the dresser waits in a fixed position on the workpiece side, forming a clear "machining position - dressing position" dual-station switching logic.

[0097] Two to three diamond rollers can be installed on the spindle of the grinding wheel dresser 7, namely a first diamond roller 7a, a second diamond roller 7b, and a third diamond roller 7c. Each diamond roller is selected and installed according to actual dressing requirements. Specifically, the first diamond roller 7a is used to dress worm gear grinding wheels (installed on the first spindle 11 for worm gear grinding) and multi-line grinding wheels (installed on the fourth spindle 14 for rough thread grinding); the second diamond roller 7b is used to dress external thread grinding wheels (installed on the second spindle 13 for fine thread grinding) and external cylindrical grinding wheels (installed on the third spindle 8 for external cylindrical grinding). Each diamond roller drives the grinding wheel dresser 7 to swing around the A3 axis via the dresser swing angle device 71, switching to the dressing position to perform in-situ dressing of the grinding wheels on different spindles. Preferably, the third diamond roller 7c is installed as needed.

[0098] The top of the mounting column 52 is provided with an inspection port 522, which facilitates the maintenance and repair of internal wiring, air pipes, cooling pipes, etc.

[0099] The machine tool of the present invention has 10 CNC coordinate axes: X, Z, C, A1, A2, B, Y, A3, B1, and W. All linear and rotary axes are controlled by a closed loop.

[0100] Example 2 (Processing Method Example - Roller Gear Hobbing)

[0101] This embodiment takes gear hobbing as an example to illustrate the method of performing gear hobbing on the roller teeth of a planetary roller screw using the machine tool of the present invention.

[0102] First, the planetary roller screw workpiece to be processed is clamped between the workpiece spindle 4 and the tailstock 6, and the workpiece is driven by the workpiece spindle 4 to rotate around the C-axis. After the workpiece is clamped once, it remains clamped throughout the entire processing until all processes (including gear hobbing, rough thread grinding, fine thread grinding, and external cylindrical grinding) are completed.

[0103] After clamping, the workpiece is initially positioned and tool set using the detection device 15 to determine the initial position of the workpiece in the machine tool coordinate system and the angular phase reference between the teeth and the thread.

[0104] During gear hobbing, the first spindle 11 is switched to the working position by rotating the turntable assembly 5 around the B-axis. The first swing angle mechanism 9 drives the first spindle 11 to swing around the A1-axis, adjusting the hobbing cutter on the first spindle 11 to form the required angle with the workpiece axis. This angle is determined according to the helix angle or entry angle of the tooth to be machined. Then, the first spindle 11 is started, and the X-axis transmission mechanism 3 and Z-axis transmission mechanism 2 are linked to feed the workpiece teeth, performing gear hobbing.

[0105] After the gear hobbing is completed, the teeth can be inspected in place using the detection device 15 to obtain the machining accuracy data. The workpiece does not need to be disassembled during the entire machining process, ensuring the phase synchronization accuracy between the teeth and the subsequently machined threads.

[0106] Example 3 (Processing Method Example - Roller Thread Machining)

[0107] This embodiment takes thread processing as an example to illustrate the method of processing planetary roller screw roller threads using the machine tool of the present invention.

[0108] After completing the gear machining (or before gear machining), thread machining is performed. First, the fourth spindle 14 is switched to the working position by rotating the turntable assembly 5 around the B-axis (when the fourth spindle 14 is an optional installation). The multi-spindle grinding wheel on the fourth spindle 14 is started to rotate, and the X-axis transmission mechanism 3 and Z-axis transmission mechanism 2 are linked to feed. The multi-spindle grinding wheel grinds multiple helical lines of the thread simultaneously in one pass, quickly removing most of the excess material from the thread.

[0109] After rough grinding, the second spindle 13 is switched to the working position by rotating the turntable assembly 5 around the B-axis. Before performing thread fine grinding, the grinding wheel is first aligned using the W-axis feed mechanism: the operator inputs the W-axis position command through the touch panel of the CNC system or by turning the handwheel, causing the W-axis feed mechanism to drive the thread grinding wheel to move along its own axis until the working surface of the grinding wheel precisely coincides with the rotation center of the A2 axis, completing the alignment. After alignment, the second swing angle mechanism 12 drives the second spindle 13 to swing around the A2 axis, adjusting the thread grinding wheel on the second spindle 13 to form the required angle with the workpiece axis. This angle is determined according to the helix angle of the thread to be processed. Then, the second spindle 13 is started, and the grinding wheel is fed along its own axis by the W-axis feed mechanism to perform fine grinding on the workpiece thread, ensuring micron-level dimensional accuracy and ideal surface quality.

[0110] The rough and fine grinding of the thread is completed continuously without disassembling the workpiece in between. The rough and fine grinding are driven by independent spindles (fourth spindle 14 and second spindle 13), each using the optimal grinding wheel linear speed, cooling method and grinding parameters.

[0111] After precision grinding is completed, the threads can be inspected in place by the detection device 15 to obtain thread machining accuracy data.

[0112] Example 4 (Processing Method Example - Complete Process Flow)

[0113] This embodiment illustrates a method for fully machining planetary roller screw rollers using the machine tool of the present invention.

[0114] The planetary roller screw workpiece to be machined is clamped between the workpiece spindle 4 and the tailstock 6 in one go, and the workpiece is driven by the workpiece spindle 4 to rotate around the C-axis. The workpiece is initially positioned and tool-set by the detection device 15 to determine the angular phase reference between the teeth and the thread.

[0115] When the third mounting position has the third spindle 8 installed and the fourth mounting position has the fourth spindle 14 installed, the following steps are executed in sequence:

[0116] S6: By rotating the turntable assembly 5 around the B-axis, the fourth spindle 14 is switched to the working position, and the multi-line grinding wheel is started to perform multi-line rough grinding on the thread.

[0117] S4-0 (Alignment Step): The second spindle 13 is switched to the working position by rotating the turntable assembly 5 around the B axis. The W axis position command is input through the touch operation panel of the CNC system or by shaking the handwheel, so that the W axis feed mechanism drives the thread grinding wheel to move along its own axis until the working surface of the grinding wheel is precisely aligned with the rotation center of the A2 axis, thus completing the alignment adjustment before grinding.

[0118] S4: The second swing angle mechanism 12 drives the second main shaft 13 to swing around the A2 axis to the angle that matches the thread helix angle, and controls the axial feed of the grinding wheel through the W-axis feed mechanism to perform single-line fine grinding of the thread.

[0119] S3: The first spindle 11 is switched to the working position by rotating the turntable assembly 5 around the B axis. The first swing angle mechanism 9 drives the first spindle 11 to swing around the A1 axis to the angle that matches the helix angle of the teeth, and performs tooth machining (gear hobbing or gear grinding).

[0120] S5: The third spindle 8 is switched to the working position by rotating the turntable assembly 5 around the B axis to perform external cylindrical grinding.

[0121] When the gear-cutting grinding wheel mounted on the first spindle 11 or the thread-grinding grinding wheel mounted on the second spindle 13 needs dressing, a dressing step can be inserted between any of the above steps: by rotating the turntable assembly 5 around the B-axis, the corresponding spindle is switched to the dressing position facing the grinding wheel dresser 7—the grinding wheel dresser 7 maintains a constant spatial position in the machine tool coordinate system—the grinding wheel dresser 7 swings around the A3-axis, adjusting the corresponding diamond roller mounted on its spindle to the dressing posture, and performing in-situ dressing of the grinding wheel; after dressing is completed, by rotating the turntable assembly 5 around the B-axis, the corresponding spindle is switched back to the working position to continue machining.

[0122] In the above steps, S6 (multi-line rough grinding of threads) must be performed before S4 (single-line fine grinding of threads); the order of S3 (gear machining), S4, and S5 (external cylindrical grinding) can be adjusted according to actual machining requirements. For example, a typical process flow is: turning → heat treatment → external cylindrical grinding (S5) → rough thread grinding (S6) → gear machining (S3) → fine thread grinding (S4), where the arrangement of S5, S6, S3, and S4 can be adaptively adjusted according to the heat treatment state of the workpiece, the blank allowance, and the accuracy requirements. The A1 axis and A2 axis are independent of each other, and are independently and steplessly adjusted for the helix angle of the teeth and the helix angle of the threads, respectively, without interfering with each other.

[0123] After all machining is completed, the detection device 15 performs in-situ detection on each machined part to obtain complete machining accuracy data. Throughout the entire machining process, the workpiece is always kept in a single clamping state, eliminating the phase accumulation error caused by repeated positioning in sequential machining from the root.

[0124] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art, simple deductions or substitutions without departing from the concept of the present invention are all within the protection scope of the present invention.

Claims

1. A machine tool for combined thread and gear machining, characterized in that, The machine includes a bed (1), on which a Z-axis transmission mechanism (2) and an X-axis transmission mechanism (3) are provided. A turntable assembly (5) is rotatably provided on the X-axis transmission mechanism (3). A first swing angle mechanism (9) and a second swing angle mechanism (12) are provided on the turntable assembly (5). A first spindle (11) is movably provided on the first swing angle mechanism (9), and a second spindle (13) is provided on the second swing angle mechanism (12). The first swing angle mechanism (9) and the second swing angle mechanism (12) are located on opposite sides of the turntable assembly (5) and are rotatably provided around mutually independent axes A1 and A2. A workpiece spindle (4) is provided on the Z-axis transmission mechanism (2). A dresser swing angle device (71) is fixedly installed on the side of the workpiece spindle (4) near the X-axis transmission mechanism (3). A grinding wheel dresser (7) is rotatably installed on the dresser swing angle device (71). The grinding wheel dresser (7) swings independently around the A3 axis. The grinding wheel dresser (7) has a fixed spatial position relationship with the workpiece spindle (4) in the machine tool coordinate system. The grinding wheel dresser (7) is located between the workpiece spindle (4) and the turntable assembly (5). The Z-axis transmission mechanism (2) is equipped with a detection device (15), which is mounted on the same mounting platform as the workpiece spindle (4). The two are linked together along the Z-axis direction with the Z-axis transmission mechanism (2). The detection device (15) is used to perform in-situ detection on the workpiece and / or the processing part. The turntable assembly (5) has four mounting positions, wherein: The first mounting position is provided with the first swing angle mechanism (9) and the first spindle (11). The first spindle (11) is a tooth profile machining spindle, which is used to install hobbing tools or tooth profile machining grinding wheels to realize hobbing or tooth grinding of the workpiece. The second mounting position is provided with the second swing angle mechanism (12) and the second spindle (13). The second spindle (13) is a thread finishing spindle, which is used to install a thread grinding wheel to achieve thread finishing of the workpiece. The third mounting position is the first optional mounting position, which is used to selectively install the third spindle (8) or leave it empty. The third spindle (8) is an external cylindrical grinding spindle, which is used to install an external cylindrical grinding wheel to realize the external cylindrical grinding of the workpiece. The fourth mounting position is the second optional mounting position, which is used to selectively install the fourth spindle (14) or leave it empty. The fourth spindle (14) is a thread roughing spindle, which is used to install a multi-line grinding wheel to achieve rough grinding of the workpiece thread. The first spindle (11) and the second spindle (13) are mandatory configurations, while the third spindle (8) and the fourth spindle (14) are optional configurations. The turntable assembly (5) rotates around the B-axis, allowing the spindle in any mounting position to selectively switch to either the working position facing the workpiece spindle (4) or the dressing position facing the grinding wheel dresser (7). The grinding wheel dresser (7) maintains a fixed spatial position in the machine tool coordinate system. Each spindle switches to the dressing position by rotating around the B-axis through the turntable assembly (5), so that the grinding wheels on different spindles can share the same grinding wheel dresser (7) for in-situ dressing.

2. The thread and gear composite machining tool according to claim 1, characterized in that, The dressing angle device (71) includes a dressing angle body, a dressing angle shaft, and a dressing angle rotating plate. The dressing angle body is fixedly installed on the side of the workpiece spindle (4) near the X-axis transmission mechanism (3). One end of the dressing angle shaft is rotatably connected to the dressing angle body, and the other end of the dressing angle shaft is fixedly connected to the dressing angle rotating plate. The grinding wheel dresser (7) is fixedly installed on the dressing angle rotating plate. An angle encoder is provided on the dressing angle shaft to detect the swing angle of the dressing angle rotating plate around the A3 axis. The angle encoder is connected to the CNC system of the machine tool to achieve precise closed-loop control of the dressing angle. The dressing angle device (71) is also provided with a locking mechanism. The locking mechanism is used to lock the dressing angle rotating plate and the dressing angle body after the grinding wheel dresser (7) swings to the target angle to maintain the stability of the dressing posture.

3. The thread and gear composite machining tool according to claim 1, characterized in that, The Z-axis transmission mechanism (2) is provided with a center frame (16), which is mounted on the same mounting platform as the workpiece spindle (4). The two are linked together along the Z-axis direction with the Z-axis transmission mechanism (2). The center frame (16) is used to provide auxiliary support for the outer circle of the workpiece.

4. The thread and gear composite machining tool according to claim 1, characterized in that, The detection device (15) is used for initial position setting and / or machining accuracy detection of the workpiece.

5. The thread and gear composite machining tool according to claim 1, characterized in that, The detection device (15) includes a probe or probe head, which is communicatively connected to the CNC system of the machine tool.

6. The thread and gear composite machining tool according to claim 1, characterized in that, When the first spindle (11) is equipped with a hobbing cutter, it performs hobbing; when it is equipped with a worm grinding wheel, it performs worm grinding; and when it is equipped with a profile grinding wheel, it performs profile grinding.

7. The thread and gear composite machining tool according to claim 1, characterized in that, The second spindle (13) is equipped with a thread grinding wheel for thread grinding of the workpiece.

8. The thread and gear composite machining tool according to claim 1, characterized in that, The third spindle (8) is equipped with an external cylindrical grinding wheel for external cylindrical grinding of the workpiece.

9. The thread and gear composite machining tool according to claim 1, characterized in that, The fourth spindle (14) is equipped with a multi-line grinding wheel. The outer circumferential surface of the multi-line grinding wheel is provided with multiple annular grinding teeth. Each annular grinding tooth is arranged along the axial direction of the grinding wheel and simultaneously grinds multiple spiral lines of the thread in one pass.

10. The thread and gear composite machining tool according to claim 1, characterized in that, The turntable assembly (5) includes a turntable (51), a mounting column (52), and a turntable drive device. The mounting column (52) is fixedly mounted on the turntable (51). The mounting column (52) has four mounting surfaces (521) that correspond to the four mounting positions. The turntable drive device is connected to the turntable (51) to drive the turntable (51) to rotate around the B-axis.

11. The thread and gear composite machining tool according to claim 10, characterized in that, The top of the mounting column (52) is provided with an inspection port (522).

12. The thread and gear composite machining tool according to claim 1, characterized in that, The first swing angle mechanism (9) includes a first swing angle body (91), a first swing angle shaft and a first swing angle rotating plate (92). A Y-direction transmission mechanism is provided on the first swing angle rotating plate (92). The first swing angle body (91) is rotatably connected to the first swing angle rotating plate (92) through the first swing angle shaft. The first swing angle body (91) is provided on one side of the turntable assembly (5). The Y-direction transmission mechanism feeds along the axial direction of the first main shaft (11), and the Y-direction changes direction as the first swing angle mechanism (9) swings around the A1 axis.

13. The thread and gear composite machining tool according to claim 12, characterized in that, The Y-direction transmission mechanism includes a Y-direction guide rail (93), a Y-direction slide plate (94), and a Y-direction drive device (95). The Y-direction guide rail (93) is disposed on the first swing angle rotating plate (92), the first main shaft (11) is fixedly installed on the Y-direction slide plate (94), and the Y-direction drive device (95) is disposed at the rear end of the first swing angle rotating plate (92) and drives the Y-direction slide plate (94) to move back and forth along the length direction of the Y-direction guide rail (93).

14. The thread and gear composite machining tool according to claim 1, characterized in that, The second swing angle mechanism (12) includes a second swing angle body (121), a second swing angle shaft, and a second swing angle rotating plate (122). The second main shaft (13) is fixedly installed on the second swing angle rotating plate (122). The second swing angle body (121) is disposed on the side of the turntable assembly (5) away from the first swing angle mechanism (9). The second swing angle body (121) is rotatably connected to the second swing angle rotating plate (122) through the second swing angle shaft.

15. The thread and gear composite machining tool according to claim 1, characterized in that, Two to three diamond rollers can be installed on the spindle of the grinding wheel dresser (7), namely the first diamond roller (7a), the second diamond roller (7b) and the third diamond roller (7c). Each diamond roller is selected and installed according to the dressing requirements. The first diamond roller (7a) is used to dress worm grinding wheels and multi-line grinding wheels, and the second diamond roller (7b) is used to dress external thread grinding wheels and external cylindrical grinding wheels.

16. The thread and gear composite machining tool according to claim 1, characterized in that, The Z-axis transmission mechanism (2) may also be optionally provided with a tailstock (6), which is coaxially opposite to the workpiece spindle (4) and is used to assist in clamping the workpiece.

17. The thread and gear machining tool according to any one of claims 1 to 16, characterized in that, The X-axis, Z-axis, C-axis, A1-axis, A2-axis, B-axis, Y-axis, A3-axis, B1-axis, and W-axis of the machine tool all adopt full closed-loop control.

18. A machining method for a combined thread and gear machining machine tool, characterized in that, The machining process, performed using a thread and gear machining tool according to any one of claims 1 to 17, includes the following steps: S1: The shaft-type workpiece to be processed is clamped between the workpiece spindle (4) and the tailstock (6) in one go, and the workpiece is driven to rotate around the C-axis by the workpiece spindle (4); S2: The required spindle is switched to the working position by the movement of the X-axis transmission mechanism (3) and / or the Z-axis transmission mechanism (2) and the rotation of the turntable assembly (5) around the B axis; S2-1: When the gear grinding wheel installed on the first spindle (11) or the thread grinding wheel installed on the second spindle (13) needs to be dressed, the corresponding spindle is switched to the dressing position facing the grinding wheel dresser (7) by rotating the turntable assembly (5) around the B axis. The grinding wheel dresser (7) maintains a constant spatial position in the machine tool coordinate system. After the corresponding spindle rotates to the dressing position through the B axis, it forms a dressing relationship with the grinding wheel dresser (7). The grinding wheel dresser (7) swings around the A3 axis to adjust the corresponding diamond roller installed on its spindle to the dressing posture and dress the grinding wheel in place. After dressing, the corresponding spindle is switched back to the working position by rotating the turntable assembly (5) around the B axis to continue processing. S3: When performing tooth machining, the first spindle (11) is switched to the working position by rotating the turntable assembly (5) around the B axis. The first spindle (11) is driven to swing around the A1 axis by the first swing angle mechanism (9) to adjust the angle between the hobbing cutter or tooth profile machining wheel on the first spindle (11) and the workpiece axis so as to match the helix angle or cutting angle of the tooth to be machined. Then the first spindle (11) is started to perform hobbing or tooth grinding on the workpiece teeth. S4: When performing thread finishing, the second spindle (13) is switched to the working position by rotating the turntable assembly (5) around the B axis. The second spindle (13) is driven to swing around the A2 axis by the second swing angle mechanism (12) to adjust the angle between the thread grinding wheel on the second spindle (13) and the workpiece axis so as to match the helix angle of the thread to be processed. Then the second spindle (13) is started to perform thread finishing on the workpiece. When the third spindle (8) is installed in the third mounting position, the processing method further includes step S5: the third spindle (8) is switched to the working position by rotating the turntable assembly (5) around the B axis, and the external cylindrical grinding wheel on the third spindle (8) is started to perform external cylindrical grinding on the workpiece; When the fourth spindle (14) is installed in the fourth mounting position, the processing method further includes step S6: before step S4, the fourth spindle (14) is switched to the working position by rotating the turntable assembly (5) around the B axis, and the multi-line grinding wheel on the fourth spindle (14) is started to rotate, and the multi-line grinding wheel grinds multiple spiral lines of the thread simultaneously in one pass; The A1 axis and the A2 axis are independent swing axes; wherein, step S6 must be executed before step S4, and the execution order of steps S3, S4 and S5 can be interchanged according to the workstation configuration and processing requirements.

19. The machining method of the thread and gear composite machining machine tool according to claim 18, characterized in that, When the third mounting position and the fourth mounting position are simultaneously equipped with the third spindle (8) and the fourth spindle (14), step S6 must be performed before step S4. The order of steps S3, S4 and S5 can be adjusted according to processing requirements.

20. The machining method of the thread and gear composite machining machine tool according to claim 18, characterized in that, It also includes step S0: before step S3 and / or S4, the workpiece is initially positioned by the detection device (15) to determine the initial position of the workpiece in the machine tool coordinate system.

21. The machining method of the thread and gear composite machining machine tool according to claim 18, characterized in that, It also includes step S7: after steps S3, S4, S5 and / or S6, the processed part is inspected by the detection device (15) to obtain processing accuracy data.

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