Linear motion axis drive system and double pendulum head structure

Abstract

The present invention provides a linear motion axis drive system and a double pendulum head structure, including a W-axis box body, a torque motor, a ball screw, a motion axis assembly, and a linear grating; the torque motor, the ball screw, and the motion axis assembly are all arranged in the W-axis box body, one end of the ball screw coaxially passes through the output port of the torque motor and is in threaded cooperation with it, and the other end of the ball screw is connected to the motion axis assembly; the linear grating is arranged outside the motion axis assembly, the linear grating real-time detects the displacement of the motion axis assembly, and the linear grating is signal-connected to the numerical control system. The torque motor directly drives the ball screw to reciprocate, and the ball screw pushes the motion axis assembly to perform a feeding motion. The transmission route is simple. By using the torque motor and the ball screw, large torque is converted into large thrust to meet the requirement of reciprocating linear feeding motion under the demand of large thrust. Moreover, the linear grating performs real-time position feedback and error compensation, which plays a role in compensating the motion error of the tool and ensuring the feed accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of machining equipment, and specifically, to a linear motion axis drive system and a double swivel head structure. Background Art

[0002] The double swivel head five-axis machining center is a machining center with high technological content and high precision, specifically used for machining complex curved surfaces. It can be used to machine many key parts with complex and special profiles, and has become a key basic equipment for the rapid research and development of the equipment manufacturing industry and advanced national defense weapon equipment products. The linear motion axis system is integrated on the double swivel head.

[0003] The existing Chinese patent application with the publication number CN202607373U discloses a main shaft feed system of a numerical control two-axis machining machine, including a servo motor, a feed motor seat, a feed motor synchronous pulley, an arc tooth type belt, a feed ball screw, a feed synchronous pulley, a guide rod, and a main shaft. The servo motor is fixed on the feed motor seat, and the servo motor is sequentially connected to the feed synchronous pulley through the feed motor synchronous pulley and the arc tooth type belt, and drives the feed ball screw through the feed synchronous pulley to complete the main shaft feed.

[0004] The transmission route of the linear motion axis drive system in the prior art is complex, resulting in low precision and large mechanical wear of the linear motion axis system, and there are areas for improvement. Summary of the Invention

[0005] Aiming at the defects in the prior art, the purpose of the present invention is to provide a linear motion axis drive system and a double swivel head structure.

[0006] According to a linear motion axis drive system provided by the present invention, it includes a W-axis box body, a torque motor, a ball screw, a motion axis assembly, and a linear grating; the torque motor, the ball screw, and the motion axis assembly are all arranged in the W-axis box body. The torque motor is firmly installed at one end in the W-axis box body. One end of the ball screw coaxially passes through the output port of the torque motor and is in threaded cooperation with it. The other end of the ball screw is connected to the motion axis assembly, and the motion direction of the ball screw is the same as the motion direction of the motion axis assembly; the linear grating is arranged outside the motion axis assembly. The linear grating real-time detects the displacement of the motion axis assembly, and the linear grating is signal-connected to the numerical control system.

[0007] Preferably, it further includes a motor seat. The motor seat is firmly connected to the W-axis box body. The torque motor is firmly installed on the motor seat, and the structure of the motor seat is symmetrically distributed with respect to the central axis of the torque motor.

[0008] Preferably, the motor seat is a cylindrical motor mounting portion and a connecting bracket, the central axis of the motor mounting portion is colinear with the central axis of the electric spindle, and a group of connecting brackets are fastened and connected on opposite sides of the motor mounting portion.

[0009] Preferably, a liquid cooling chamber is integrated in the motor base, and the liquid cooling chamber is connected to an external pipeline.

[0010] Preferably, the rotor of the torque motor is fastened to the motor connecting shaft, and the end of the motor connecting shaft away from the spindle housing is fastened to the screw nut, one end of the ball screw coaxially passes through the motor connecting shaft and moves along its axial direction, and the end of the ball screw passing through the motor connecting shaft is threadedly connected to the screw nut.

[0011] Preferably, a cross roller ring and a ring seat are provided on the side of the motor connecting shaft close to the main shaft housing; the central axes of the ring seat, the cross ball ring and the motor connecting shaft are collinear; the ring seat is tightly connected to the W-axis housing, the outer ring of the cross roller ring is tightly connected to the ring seat, and the inner ring of the cross roller ring is connected to the motor connecting shaft.

[0012] Preferably, one end of the ball screw away from the screw nut is fastened with a screw connecting seat, the screw connecting seat is located on the side of the collar seat away from the torque motor, and the screw connecting seat is coaxially fastened with the spindle housing.

[0013] Preferably, the screw connecting seat gradually extends and expands from the connection point between the screw connecting seat and the ball screw in a direction away from the ball screw.

[0014] Preferably, a movable sealing assembly is provided at the connection between the motion shaft assembly and the W-axis housing; wherein, the movable sealing assembly includes a sealing gasket, a waterproof plate and a special ring, the sealing gasket is arranged between the waterproof plate and the W-axis housing, the special ring is embedded in the waterproof plate, and the special ring is in line contact with the main shaft housing.

[0015] A double swing head structure provided according to the present invention adopts the linear motion shaft transmission system described in any one of claims 1 to 9, and also includes an A-axis component and a B-axis component, wherein the A-axis component is connected to the B-axis component and drives it to rotate, and the B-axis component is connected to the W-axis box and drives it to swing.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. In the present invention, a torque motor directly drives a ball screw to reciprocate, and the ball screw pushes a moving shaft assembly to achieve a feeding motion. Its transmission route is simple. By adopting a torque motor and a ball screw, large torque is converted into large thrust, which can meet the requirement of reciprocating linear feeding motion under the demand of large thrust. Moreover, a linear grating performs real-time position feedback and error compensation, which plays a role in compensating the motion error of the tool and ensures the feed accuracy of the motorized spindle.

[0018] 2. In the present invention, with the drive mode of direct drive by a torque motor, the load is directly connected to the motor rotor. Compared with the traditional servo motor combined with a speed reducer transmission mechanism, it reduces mechanical transmission and mechanical friction, and has the advantages of high precision and high dynamic performance.

[0019] 3. In the present invention, through the overall symmetrical design, the overall structure has good interchangeability, uniform stress, and is compact. The assembly efficiency is high, the requirements for part maintenance are low. It has a small volume, small deformation, large rigidity, high reliability and long service life, and can be applied to working conditions with larger loads.

[0020] 4. In the present invention, the motor connecting shaft is supported by a crossed roller collar and a collar seat, which reduces the tipping moment caused by the radial load, that is, reduces the deformation of the structure, obtains a stable rotational motion, and improves the rigidity and rotational accuracy of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the detailed description of the non-restrictive embodiments with reference to the following drawings, other features, objects and advantages of the present invention will become more apparent:

[0022] Figure 1 is a schematic cross-sectional view mainly showing the overall structure of the linear motion axis system of the present invention;

[0023] Figure 2 is a schematic external structure view mainly showing the W-axis housing of the present invention;

[0024] Figure 3 is a schematic view mainly showing the overall structure of the motor base of the present invention;

[0025] Figure 4 is a schematic installation structure view mainly showing the pressing block outside the spindle housing of the present invention;

[0026] Figure 5 is a schematic external structure view mainly showing the spindle housing of the present invention.

[0027] As shown in the figure:

[0028] W-axis housing 1 Linear guide 13

[0029] Housing cover 2 Screw connection seat 14

[0030] Housing rear cover 3 Motorized spindle 15

[0031] Lead screw nut 4, spindle housing 16

[0032] Ball screw 5, slider 17

[0033] Motor base 6, gasket 18

[0034] Torque motor 7, waterproof plate 19

[0035] Motor connecting shaft 8, Tecalemit ring 20

[0036] Locking nut 9, adapter plate 21

[0037] Crossed roller collar 10, hard limit 22

[0038] Collar seat 11, anti-collision block 23

[0039] Guide rail lock 12, linear grating 24

[0040] Press block 25 Specific embodiments

[0041] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all fall within the protection scope of the present invention.

[0042] As Figure 1 shown, a linear motion shaft drive system according to the present invention includes a W-axis housing 1, a motion shaft assembly, a linear drive assembly, a linear guide rail 13, and a slider 17.

[0043] The motion shaft assembly includes a spindle housing 16 and an electric spindle 15, and the electric spindle 15 is coaxially installed in the spindle housing 16. The motion shaft assembly and the linear drive assembly are linearly arranged in the W-axis housing 1. In particular, the spindle housing 16 and the linear drive assembly are linearly arranged, the structure of the linear drive assembly is symmetrically arranged with the central axis of the spindle housing 16 as the axis of symmetry, and the acting point of the force of the linear drive assembly on the spindle housing 16 is located at the central axis of the spindle housing 16. The linear drive assembly drives the spindle housing 16 to reciprocate along the axis of the spindle housing 16, so as to ensure that the force applied by the linear drive assembly to the spindle housing 16 is stable and reliable.

[0044] The linear drive assembly includes a torque motor 7, a lead screw nut 4, a ball screw 5, and a motor connecting shaft 8.

[0045] Specifically: The ball screw 5, torque motor 7, electric spindle 15, and spindle housing 16 are all installed in the W-axis housing 1. The torque motor 7, ball screw 5, and spindle housing 16 are linearly arranged in the W-axis housing 1, and the central axes of the torque motor 7, ball screw 5, electric spindle 15, and spindle housing 16 are collinear. The spindle housing 16 is arranged on the 16-axis in the W-axis housing 1, and the structure of the spindle housing 16 is symmetrically arranged with its central axis as the axis of symmetry. The structure of the electric spindle 15 is symmetrically arranged with its central axis as the axis of symmetry. Through the symmetrically arranged spindle housing 16 and electric spindle 15, the compactness of the installation in the W-axis housing 1 during movement can be further improved.

[0046] More specifically: The torque motor 7 is firmly installed in the middle of one end in the W-axis housing 1. The lead screw nut 4 is installed at the output port of the torque motor 7. The torque motor 7 drives the lead screw nut 4 to rotate. One end of the ball screw 5 is coaxially threaded through the lead screw nut 4, and one end of the ball screw 5 coaxially passes through the output port of the torque motor 7. The other end of the ball screw 5 is firmly connected to the spindle housing 16. The end of the spindle housing 16 away from the ball screw 5 extends out of the W-axis housing 1, and the electric spindle 15 is coaxially installed in the spindle housing 16.

[0047] The torque motor 7 drives the lead screw nut 4 to rotate, thereby driving the ball screw 5 to reciprocate along the axial direction of the electric spindle 15, pushing the spindle housing 16 to reciprocate along the axial direction of the electric spindle 15, and further driving the electric spindle 15 to reciprocate along its axial direction. Through the direct drive method of the torque motor 7, the load is directly connected to the motor rotor. Compared with the traditional servo motor with a reducer transmission mechanism, it reduces mechanical transmission and mechanical friction and has the advantages of high precision and high dynamic performance. By using the torque motor 7 and the ball screw 5, large torque is converted into large thrust, which can meet the requirement of reciprocating linear feed movement under large thrust.

[0048] Furthermore, it also includes a motor base 6. The motor base 6 is arranged in the W-axis housing 1 and is firmly connected to the inner wall of the W-axis housing 1. The torque motor 7 is coaxially and firmly installed on the motor base 6. The motor base 6 includes a cylindrical motor installation part and a connecting bracket. The central axis of the motor installation part is collinear with the central axis of the electric spindle 15. A set of connecting brackets are respectively and firmly connected to the two opposite sides of the motor installation part. During installation, both connecting brackets are respectively connected to the W-axis housing 1 by bolts, and the stator of the torque motor 7 is firmly installed in the motor installation part by bolts. The structure of the motor base 6 is symmetrically distributed with the central axis of the torque motor 7 as the axis of symmetry, and a liquid cooling cavity is arranged in the motor base 6, and the liquid cooling cavity is communicated with an external pipeline.

[0049] By integrating the liquid cooling cavity into the motor base 6, there is no need to add an additional water cooling structure, reducing the installation space and cost. It should be noted that there is enough space for the ball screw 5 to reciprocate between the end of the motor base 6 and the W-axis box body 1.

[0050] The rotor of the torque motor 7 is fixedly connected with a motor connecting shaft 8. The central axis of the motor connecting shaft 8 is collinear with the central axis of the torque motor 7. The lead screw nut 4 is fixedly connected with the end of the motor connecting shaft 8 far from the main shaft box body 16. The ball screw 5 coaxially passes through the motor connecting shaft 8 and is movably matched with it. The ball screw 5 can move along the axial direction of the motor connecting shaft 8. The end of the lead screw nut 4 passing through the motor connecting shaft 8 is in threaded engagement with the ball screw 5 to rotate, converting the rotational motion of the lead screw nut 4 into the linear motion of the ball screw 5.

[0051] On one side of the motor connecting shaft 8 close to the main shaft box body 16, there are arranged a crossed roller collar 10 and a collar seat 11. The central axis of the collar seat 11 is collinear with the central axis of the motor connecting shaft 8. The collar seat 11 is fixedly connected with the W-axis box body 1. The outer ring of the crossed roller collar 10 is fixedly connected with the collar seat 11, and the inner ring of the crossed roller collar 10 is connected with the motor connecting shaft 8.

[0052] One end of the ball screw 5 far from the lead screw nut 4 is fixedly connected with a screw connection seat 14 through a lock nut 9. The screw connection seat 14 is located on the side of the collar seat 11 away from the torque motor 7, and the screw connection seat 14 is coaxially and fixedly connected with the main shaft box body 16. The screw connection seat 14 gradually extends and expands from its connection with the ball screw 5 in the direction away from the ball screw 5. Thus, the force exerted by the screw connection seat 14 on the main shaft box body 16 is more uniform.

[0053] As the motor connecting shaft 8 and the lead screw nut 4 rotate with the torque motor 7, the rotation of the lead screw nut 4 is converted into the linear motion of the ball screw 5. The ball screw 5 pushes the main shaft box body 16 to reciprocate along the axis of the motorized spindle 15 through the screw connection seat 14. The motor connecting shaft 8 is supported by the crossed roller collar 10 and the collar seat 11, reducing the overturning moment caused by the radial load, that is, reducing the deformation of the structure, obtaining a stable rotational motion, and improving the rigidity and rotational accuracy of the structure.

[0054] Furthermore, the flange on the motorized spindle 15 and the end face of the main shaft box body 16 are connected by screws.

[0055] A feasible implementation of the present application is that a linear guide rail 13 is provided on the outer side wall of the main shaft housing 16, and the length direction of the linear guide rail 13 is the same as the movement direction of the main shaft housing 16. A slider 17 is provided on the inner wall of the W-axis housing 1, and the slider 17 corresponds to the linear guide rail 13 and is in sliding fit therewith. Thus, the stability of the reciprocating movement of the main shaft housing 16 is improved. Four groups of linear guide rails 13 are symmetrically arranged at equal intervals on the circumferential side of the outer wall of the main shaft housing 16. The overall structural layout is symmetrical, the force is evenly distributed, the rigidity is large, and the deformation is small. Any linear guide rail 13 corresponds to a plurality of sliders 17, and the plurality of sliders 17 are arranged at equal intervals along the movement direction of the main shaft housing 16.

[0056] Another feasible implementation is that the linear guide rail 13 is provided on the inner wall of the W-axis housing 1, and the slider 17 is provided on the outer side wall of the main shaft housing 16. Other arrangement methods are the same as those of the above implementation, only the positions of the linear guide rail 13 and the slider 17 are exchanged, and it still belongs to the protection scope of the present application.

[0057] A pressure block 25 is further provided on the outer side wall of the main shaft housing 16, and the pressure block 25 limits the linear guide rail 13. The pressure block 25 presses against the linear guide rail 13 and the backrest surface of the linear guide rail 13 to prevent the linear guide rail 13 from deviating from its original position due to vibration and impact on the W-axis, thereby affecting the accuracy.

[0058] An anti-collision block 23 is provided on the outer wall of the main shaft housing 16, and hard limits 22 are respectively provided at both ends of the W-axis housing 1. The anti-collision block 23 moves along with the main shaft housing 16, and the anti-collision block 23 and the hard limit 22 cooperate to limit the movement range of the main shaft housing 16. The above mechanical limit structure plays a protective role.

[0059] It further includes a guide rail lock 12. A transfer plate 21 is connected between the guide rail lock 12 and the W-axis housing 1. The guide rail lock 12 acts on the guide rail, and the guide rail lock 12 is signal-connected to a normally closed solenoid valve. The normally closed solenoid valve can quickly respond to start the guide rail lock 12 when powered off, realizing the instant braking function.

[0060] An end of the W-axis housing 1 extending out of the main shaft housing 16 is provided with a movable sealing assembly. Among them, the movable sealing assembly includes a sealing gasket 18, a waterproof plate 19 and a Tecalemit ring 20. The sealing gasket 18 is arranged between the waterproof plate 19 and the W-axis housing 1. The Tecalemit ring 20 is embedded on the waterproof plate 19, and the Tecalemit ring 20 is in line contact with the main shaft housing 16. The waterproof plate 19 forms the first protection during the working process, blocking a large amount of cutting fluid and cutting debris. The Tecalemit ring 20 forms the second protection, blocking a small amount of cutting fluid and cutting debris. And while the Tecalemit ring 20 achieves movable sealing, it also reduces the friction with the moving components.

[0061] In the middle of the axial direction of the linear guide 13, there is a linear grating 24, which is fixedly installed on the spindle housing 16 to perform real-time position feedback and error compensation. Due to the modification of electrical debugging parameters and the increase of mechanical errors, there is a large difference between the position of the linear axis of the motorized spindle 15 and the position required by the numerical control system instructions. The linear grating 24 detects whether the actual displacement of the linear axis of the motorized spindle 15 conforms to the instructions issued by the numerical control system, observes and tracks the feed error; if the linear axis of the motorized spindle 15 does not reach the accurate position due to mechanical reasons or the like, the linear grating 24, as a position detection element, will issue an instruction to the numerical control system to enable the linear axis of the motorized spindle 15 to reach a relatively accurate position until the resolution of the linear grating 24 cannot distinguish it, playing a role in compensating the tool movement error and ensuring the feed accuracy of the motorized spindle 15.

[0062] A housing cover plate 2 and a housing rear cover 3 are also installed on the W-axis housing 1. On the one hand, it can provide convenience for installation and maintenance, and on the other hand, it can play a protective role to prevent dust, iron filings, etc. from entering the W-axis housing 1.

[0063] It should be noted that through the overall symmetric design of the present application, the overall structure has good interchangeability, uniform stress, and compact structure. The assembly efficiency is high, the requirements for part maintenance are low. It has a small volume, small deformation, large rigidity, high reliability and long service life, and can be applicable to working conditions with large loads.

[0064] According to a double swivel head structure provided by the present invention, adopting the above-mentioned compact layout structure of the linear motion axis, it further includes an A-axis component and a B-axis component. The A-axis component is connected to and drives the B-axis component to rotate, and the B-axis component is connected to and drives the W-axis housing 1 to swing.

[0065] Those skilled in the art know that in addition to implementing the system and its various devices, modules, and units provided by the present invention in the form of pure computer-readable program code, the method steps can be logically programmed to enable the system and its various devices, modules, and units provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers, etc. to achieve the same functions. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a kind of hardware component, and the devices, modules, and units included therein for implementing various functions can also be regarded as the structures within the hardware component; the devices, modules, and units for implementing various functions can also be regarded as both software modules for implementing the method and the structures within the hardware component.

[0066] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0067] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A linear motion axis drive system, characterized in that, It comprises a W-axis housing (1), a torque motor (7), a ball screw (5), a motion axis assembly, and a linear grating (24); The torque motor (7), the ball screw (5), and the motion shaft assembly are all arranged in the W-axis housing (1); the torque motor (7) is fixedly mounted at one end in the W-axis housing (1); one end of the ball screw (5) coaxially passes through the output port of the torque motor (7) and is threadedly engaged with the output port; the other end of the ball screw (5) is connected to the motion shaft assembly; and the movement direction of the ball screw (5) is the same as the movement direction of the motion shaft assembly; The linear grating (24) is arranged outside the motion axis component, the linear grating (24) detects the displacement of the motion axis component in real time, and the linear grating (24) is connected to the numerical control system signal; It also includes a motor base (6), the motor base (6) being firmly connected to the W-axis housing (1), the torque motor (7) being firmly mounted on the motor base (6), and the structure of the motor base (6) being symmetrically distributed about the central axis of the torque motor (7); The motor seat (6) is a cylindrical motor mounting portion and a connecting bracket, the central axis of the motor mounting portion is colinear with the central axis of the electric spindle (15), and a group of connecting brackets are respectively fastened and connected on two opposite sides of the motor mounting portion; The rotor of the torque motor (7) is fixedly connected to a motor connecting shaft (8), one end of the motor connecting shaft (8) away from the spindle housing (16) is fixedly connected to a screw nut (4), one end of the ball screw (5) coaxially passes through the motor connecting shaft (8) and moves along the axial direction thereof, and one end of the ball screw (5) passing through the motor connecting shaft (8) is threadedly connected to the screw nut (4); A cross roller shaft ring (10) and a shaft ring seat (11) are provided on one side of the motor connecting shaft (8) close to the spindle housing (16); The central axes of the collar seat (11), the cross ball collar and the motor connecting shaft (8) are collinear; The shaft ring seat (11) is tightly connected to the W-axis housing (1), the outer ring of the cross roller shaft ring (10) is tightly connected to the shaft ring seat (11), and the inner ring of the cross roller shaft ring (10) is connected to the motor connecting shaft (8); One end of the ball screw (5) away from the screw nut (4) is fastened with a screw connection seat (14), the screw connection seat (14) is located on the side of the collar seat (11) away from the torque motor (7), and the screw connection seat (14) is coaxially fastened with the spindle housing (16).

2. The linear motion axis drive system according to claim 1, characterized in that, A liquid cooling cavity is integrated in the motor base (6), and the liquid cooling cavity is connected to an external pipeline.

3. The linear motion axis drive system according to claim 1, characterized in that, The connection between the screw connection seat (14) and the ball screw (5) gradually extends and expands in a direction away from the ball screw (5).

4. The linear motion axis drive system according to claim 1, characterized in that, A movable sealing assembly is provided at the connection between the motion shaft assembly and the W-axis housing (1).

5. A double swing head structure, characterized in that, The linear motion shaft transmission system according to any one of claims 1 to 4 further comprises an A-axis component and a B-axis component, wherein the A-axis component is connected to the B-axis component and drives the B-axis component to rotate, and the B-axis component is connected to the W-axis housing (1) and drives the W-axis housing to swing.

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