A machine tool spindle gearbox shifting mechanism and control method

Abstract

The present invention discloses a machine tool spindle gearbox shift mechanism and control method, including a driving mechanism, a fork rod contact piece and a plurality of gear switches, wherein the driving mechanism is connected to the fork rod and drives the fork rod to move back and forth, and the contact piece is connected to the fork rod and moves with the fork rod; when the gearbox is successfully engaged, the contact piece on the fork rod will contact the gear switch of the corresponding gear. The shifting force of the shifting mechanism of the present invention is controllable, and will not cause damage to the shifting mechanism and the gears inside the gearbox, the moving speed of the fork is controllable, the shifting is smooth, and the accuracy is higher; the method performs gear shifting when the machine tool spindle deflects, thereby reducing the risk of top teeth. In the method, if the gear shift is not in place, the reliability of the gear shifting and speed change is guaranteed through multiple gear shifting operations.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial machine tool functional components, and more specifically to a machine tool spindle gearbox shifting mechanism and a control method. Background Art

[0002] The spindles of medium and large high-end CNC machine tools are mostly equipped with shiftable gearboxes. The high / low speed gear switching is achieved through the shift mechanism to broaden the versatility of the machine tools. High-speed light cutting can be achieved in high-speed gear to process flexible materials, and low-speed heavy cutting (high cutting force) can be achieved in low-speed gear to process hard materials.

[0003] Compared with automobile gearboxes, machine tool gearboxes are designed to provide multiple speeds to the machine tool's spindle or feed system, so that the machining process can be adjusted to the most appropriate speed based on factors such as material hardness and tool type. Machine tool gearboxes need to be able to operate stably for a longer period of time, and higher precision requirements are required during precision machining.

[0004] In the prior art, there is a CNC machine tool spindle speed change logic control method with publication number CN1265938C, which uses the spindle side inertia to achieve automatic speed change, save energy, improve work efficiency, increase shift reliability, and increase the service life of the machine tool, in order to solve the technical problems of "top teeth", long time consumption, high energy consumption, and poor shift reliability when the CNC machine tool spindle changes speed. However, the gearbox shift mechanism of the above-mentioned CNC machine tool is mainly based on solenoid valve or hydraulic shift, and the disadvantages are as follows: ① The shift force is too large, which can easily cause the shift mechanism and the gears inside the gearbox to be damaged; ② The moving speed of the shift fork cannot be controlled, resulting in unsmooth or difficult shifting; ③ There is no self-locking function, and the vibration generated by the machine tool processing can easily cause the gear of the gearbox to disengage.

[0005] Based on this, a machine tool spindle gearbox shifting mechanism and a control method are proposed to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a machine tool spindle gearbox shifting mechanism and a control method to overcome the above-mentioned defects in the prior art.

[0007] The technical solution to achieve the purpose of the present invention is: a machine tool spindle gearbox shifting mechanism, including a driving mechanism, a fork rod contact piece and a plurality of gear switches, the driving mechanism is connected to the fork rod and drives the fork rod to move back and forth, the contact piece is connected to the fork rod and moves with the fork rod; when the gearbox is successfully engaged, the contact piece on the fork rod contacts the gear switch of the corresponding gear.

[0008] As a preferred embodiment, the plurality of gear switches include an S1 high-speed gear switch, an S2 low-speed gear switch and an S3 neutral switch.

[0009] As a preferred embodiment, the driving mechanism includes a housing, a shift motor, a transmission gear, a screw and a screw nut; the shift motor is fixed inside the housing, the input end of the transmission gear is connected to the output shaft of the shift motor, the output end of the transmission gear is connected to the screw, the screw nut is arranged on the screw, and the fork rod is connected to the screw nut.

[0010] As a preferred embodiment, the screw rod is a trapezoidal screw rod, and the thread lead angle of the trapezoidal screw rod is smaller than the static friction angle.

[0011] As a preferred embodiment, the shift mechanism further includes an aviation plug, and the shift motor, S1 high-speed gear switch, S2 low-speed gear switch and S3 neutral switch are electrically connected to the aviation plug respectively.

[0012] As a preferred embodiment, a position sensor is further included, and the position sensor can accurately monitor the distance of the fork rod.

[0013] As a preferred embodiment, according to the position sensor, the distance that the prime fork lever moves to the corresponding gear position is S, the pitch of the screw rod 4 is L, the speed of the screw rod is n, and the single shift time is t; the single shift time is controlled to be

[0014]

[0015] As a preferred embodiment, the single shift time t is between 0.4 seconds and 0.6 seconds.

[0016] A machine tool spindle gearbox shift control method, comprising a machine tool spindle gearbox shift mechanism, wherein the spindle motor comprises a converter, a frequency converter and a speed controller;

[0017] The specific steps are as follows:

[0018] (1) The spindle motor reduces the spindle speed to zero and keeps the controller on the converter enabled;

[0019] (2) Inputting preset left and right yaw signals to the frequency converter and speed controller;

[0020] (3) The drive mechanism is energized and the shift fork begins to move to shift gears;

[0021] (4) Determine whether the shift fork lever has moved to the corresponding gear position. If the shift fork lever has moved to the corresponding gear position, the contact piece will contact the corresponding gear switch and send a signal to confirm that the gear shift is completed;

[0022] (5) The left and right yaw signals of the frequency converter and speed controller on the spindle motor are turned off;

[0023] (6) The drive mechanism is closed;

[0024] (7) The gear shifting action is completed;

[0025] (8) The spindle motor starts to rotate;

[0026] (9) If it is determined in step (4) that the shift fork lever has not moved to the corresponding gear position, the shift fork lever returns to the initial position, and it is determined whether the shift fork lever has been returned more than five times. If not, repeat step (3);

[0027] (10) If the shift fork lever is retracted more than five times in step (9), the shift failure is confirmed and the spindle motor power is disconnected;

[0028] (11) Check the gear shift mechanism for faults.

[0029] As a preferred embodiment, the period of the spindle deflection is T, and the shift time used in one direction is t; N is a positive integer.

[0030] By adopting the above technical solution, the present invention has the following beneficial effects:

[0031] (1) When the entire system of the gearbox shift mechanism of the present invention is working, after the mechanical structure in the gearbox is successfully docked, the contact piece on the shift fork rod contacts the corresponding gear limit switch, making the performance of the gearshift mechanism more reliable and the gearshift process smoother.

[0032] (2) The present invention changes the input direction of the motor through the gear transmission mechanism and transmits the motor input to the screw mechanism; the screw rotates, driving the screw nut to move on the screw, thereby driving the fork rod fixed on the screw nut to move. The moving speed of the fork rod can be controlled by calculating and controlling the screw pitch and lead. The gear and screw transmission mechanism ensures the precise transmission of input power in terms of structural design.

[0033] (3) The present invention uses a trapezoidal screw transmission mechanism to achieve automatic self-locking after shifting. When the shifting is completed, the motor stops. Since the thread lead angle of the trapezoidal screw is smaller than the friction angle, the fork lever cannot rotate the screw no matter how much force is applied to the gearbox. This prevents the gearbox from falling off or accidentally jumping. This design can improve the stability and safety of the system.

[0034] (4) The present invention controls the circuit connection relationship between the shift motor and the gear switch through the aviation plug. After the system receives the limit switch signal, it indicates that the gear is engaged successfully. At this time, the system stops supplying power to the shift system, and the circuit layout is clear.

[0035] (5) The present invention monitors the position of the shift fork lever through a position sensor, and multiple gear switch instruments can realize redundant verification of gear engagement.

[0036] (6) The present invention can calculate and control the single gear shifting time, improve the docking accuracy of the gear shifting, reduce the risk of top teeth, and increase the service life of the gearbox.

[0037] (7) The single gear shifting time of the present invention is controlled between 0.4 seconds and 0.6 seconds, which can meet the requirements of frequent gear shifting and gear shifting time of machine tools.

[0038] (8) The shifting force of the shifting mechanism of the present invention is controllable, and will not cause damage to the shifting mechanism and the gears inside the gearbox. The moving speed of the shift fork is controllable, and the shifting is smooth and more accurate. The method shifts gears when the machine tool spindle is deflected, thereby reducing the risk of top teeth. In the method, if the gear shift is not in place, the reliability of the gear shifting and speed change is guaranteed through multiple shifting operations, and the "top teeth" phenomenon is completely avoided, and the self-diagnosis capability is strong. The method can not only conveniently and reliably realize the automatic speed control of the spindle, meet the requirements of high-speed and high-efficiency processing of CNC machine tools, but also reduce the labor intensity of workers, improve work efficiency and reliability, and increase the service life of machine tools.

[0039] (9) In the present invention, the single shift time is set to an integer multiple of the swing period, so that the gear docking accuracy is higher, the wear between the gears is reduced, and the service life is extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments and in conjunction with the accompanying drawings, wherein

[0041] Figure 1 It is the front view of the present invention.

[0042] Figure 2 It is the AA cross-sectional view of the main view of the present invention.

[0043] Figure 3 It is a logic flow chart of the present invention.

[0044] The numbers in the accompanying drawings are: 1. driving mechanism, 11. housing, 12. shift motor, 13. transmission gear, 14. screw, 15. screw nut; 2. fork rod; 3. contact piece; 4. S1 high-speed gear switch; 5. S3 neutral switch; 6. S2 low-speed gear switch; 7. aviation plug. DETAILED DESCRIPTION

[0045] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0046] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0049] In the description of the embodiments of the present invention, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when used, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0050] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The present invention is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0051] Example 1

[0052] For specific implementation, see Figure 1 and Figure 2A machine tool spindle gearbox shift control method includes a spindle motor and a shift mechanism, the spindle motor includes a converter, a frequency converter and a speed controller, the shift mechanism includes a drive mechanism 1, a fork lever 2, a contact piece 3, an S1 high-speed gear switch 4, an S2 low-speed gear switch 6 and an S3 neutral switch 5, the drive mechanism 1 is connected to the fork lever 2 and drives the fork lever 2 to reciprocate, and the contact piece 3 is connected to the fork lever 2 and moves with the fork lever 2.

[0053] The specific steps are as follows:

[0054] (1) The spindle motor reduces the spindle speed to zero and keeps the controller on the converter enabled;

[0055] (2) Inputting preset left and right yaw signals to the frequency converter and speed controller;

[0056] (3) The driving mechanism 1 is energized, and the shift fork rod 2 starts to move and shift;

[0057] (4) Determine whether the shift fork lever 2 has moved to the corresponding gear position. If the shift fork lever 2 has moved to the corresponding gear position, the contact piece 3 will contact the corresponding gear position switch and send a signal to confirm that the gear shift is completed;

[0058] (5) The left and right yaw signals of the frequency converter and speed controller on the spindle motor are turned off;

[0059] (6) Between 200 milliseconds and 500 milliseconds, the drive mechanism 1 is turned off;

[0060] (7) The gear shifting action is completed;

[0061] (8) The spindle motor starts to rotate;

[0062] (9) If it is determined in step (4) that the shift fork lever 2 has not moved to the corresponding gear position, the shift fork lever 2 returns to the initial position, and it is determined whether the shift fork lever 2 has returned more than five times. If not, repeat step (3);

[0063] (10) If the number of times the shift fork rod 2 is retracted in step (9) exceeds five times, the shift failure is confirmed and the spindle motor power is disconnected;

[0064] (11) Check the gear shift mechanism for faults.

[0065] See Figure 3 A machine tool spindle gearbox shifting mechanism, a driving mechanism 1 includes a housing 11, a shifting motor 12, a transmission gear 13, a screw 14 and a screw nut 15.

[0066] The shift motor 12 is fixed inside the housing 11, the input end of the transmission gear 13 is connected to the output shaft of the shift motor 12, the output end of the transmission gear 13 is connected to the screw 14, the screw nut 15 is arranged on the screw 14, and the fork rod 2 is connected to the screw nut 15. The shift motor 12 drives the transmission gear 13, the transmission gear 13 drives the screw 14 to rotate, and the screw 14 rotates to drive the screw nut 15 to realize the fork rod 2 to reciprocate along the axial direction of the screw 14.

[0067] For further information, see Figure 2 , the shift mechanism also includes an aviation plug 7. The power supply of the shift motor 12 is electrically connected to the ① and ③ cores of the aviation plug 7 respectively, the S1 high-speed gear switch 4 is electrically connected to the ④ core of the aviation plug 7, the S3 neutral gear switch 5 is electrically connected to the ⑤ core of the aviation plug 7, and the S2 low-speed gear switch 6 is electrically connected to the ⑥ core of the aviation plug 7. The contact piece 3 is connected to the fork rod 2 and moves with the fork rod 2. When the fork rod 6 moves to the corresponding gear position, the contact piece 3 will contact the corresponding gear switch. After the gearbox is successfully engaged, the contact piece on the fork rod will contact the limit switch of the corresponding gear position. After the shift mechanism receives the limit switch signal, it indicates that the gear is successfully engaged, and the shift mechanism stops supplying power.

[0068] Furthermore, the screw rod 14 is a trapezoidal screw rod, the thread lead angle of which is smaller than the static friction angle, and the fork rod 2 cannot rotate the screw rod 14 regardless of the force applied to the gearbox. This prevents the gearbox from falling off or accidentally jumping gears, and this design can improve the stability and safety of the system.

[0069] Furthermore, let the shift time used in one direction be t, and the period of the spindle deflection be T, N is a positive integer. At the beginning of the shifting action, the gear ring connected to the main shaft and the gear ring connected to the fork rod 2 are in a gear-to-gear alignment state. When the machine tool main shaft deflects, the gear ring connected to the main shaft deflects left and right at the same frequency, and the swing amplitude of the gear ring connected to the main shaft is set to the angle of one tooth. After a swing cycle, it can be restored to the position where the teeth are aligned. When the shifting time is an integer multiple of the spindle deflection cycle T, when the fork rod 2 moves to the gear ring position, the gear alignment with the gear ring is achieved, thereby improving the shifting accuracy, reducing the friction between the gears during shifting, and increasing the service life of the gears.

[0070] Furthermore, the shift mechanism further comprises a position sensor (not shown in the figure). The position sensor can accurately monitor the distance of the shift fork rod 2 .

[0071] Furthermore, according to the position sensor, the distance that the fork rod 2 needs to move to the corresponding gear position is S, the pitch of the screw rod 4 is L, and the rotation speed of the screw rod is n.

[0072] You can get the single shift time

[0073] By controlling the speed of the screw through the speed of the shift motor 12, the background control system can automatically convert the single shift time t, control t to be an integer multiple of the swing period T, achieve precise docking between the shift gears, and improve the accuracy and smoothness of the shift.

[0074] Wherein, the unit of S is millimeter, the unit of L is millimeter, the unit of n is rpm (revolutions per minute), and the unit of t is second.

[0075] Furthermore, a single gear shifting time is 0.4 seconds ≤ t ≥ 0.6 seconds, and a maximum gear shifting time is between two seconds and three seconds.

[0076] In summary, in this embodiment, the shifting force of the shifting mechanism is controllable, and the shifting mechanism and the gears inside the gearbox will not be damaged. The moving speed of the shift fork is controllable, the shifting is smooth, and the accuracy is higher. This method performs shifting when the machine tool spindle is deflected, thereby reducing the risk of top teeth. In this method, if the gear shift is not in place, the reliability of the gear shifting and speed change is guaranteed through multiple shifting operations, the "top teeth" phenomenon is completely avoided, and the self-diagnosis capability is strong. This method can not only conveniently and reliably realize the automatic speed control of the spindle, meet the requirements of high-speed and efficient processing of CNC machine tools, but also reduce the labor intensity of workers, improve work efficiency and reliability, and increase the service life of machine tools.

[0077] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A machine tool spindle gearbox shift mechanism, characterized in that: The invention comprises a driving mechanism (1), a shift fork rod (2), a contact piece (3) and a plurality of gear switches; the driving mechanism (1) is connected to the shift fork rod (2) and drives the shift fork rod (2) to move back and forth; the contact piece (3) is connected to the shift fork rod (2) and moves along with the shift fork rod (2); when the gearbox is successfully engaged, the contact piece (3) on the shift fork rod (2) contacts the gear switch of the corresponding gear.

2. The machine tool spindle gearbox shifting mechanism according to claim 1, characterized in that: The plurality of gear switches include an S1 high-speed gear switch (4), an S2 low-speed gear switch (6) and an S3 neutral gear switch (5).

3. The machine tool spindle gearbox shifting mechanism according to claim 2, characterized in that: The driving mechanism (1) comprises a housing (11), a shift motor (12), a transmission gear (13), a screw (14) and a screw nut (15); the shift motor (12) is fixed inside the housing (11), the input end of the transmission gear (13) is connected to the output shaft of the shift motor (12), the output end of the transmission gear (13) is connected to the screw (14), the screw nut (15) is arranged on the screw (14), and the shift fork rod (2) is connected to the screw nut (15).

4. The machine tool spindle gearbox shifting mechanism according to claim 3, characterized in that: The screw rod (14) is a trapezoidal screw rod, and the thread lead angle of the trapezoidal screw rod is smaller than the static friction angle.

5. The machine tool spindle gearbox shifting mechanism according to claim 3, characterized in that: The shift mechanism also includes an aviation plug (7), and the shift motor (12), the S1 high-speed gear switch (4), the S2 low-speed gear switch (6) and the S3 neutral switch (5) are electrically connected to the aviation plug (7) respectively.

6. The machine tool spindle gearbox shifting mechanism according to claim 3, characterized in that: A position sensor is also included, which can accurately monitor the distance of the fork rod (2).

7. A machine tool spindle gearbox shifting mechanism according to claim 6, characterized in that: According to the position sensor, the distance that the shift fork rod (2) moves to the corresponding gear position is S, the pitch of the screw rod (14) is L, the speed of the screw rod is n, and the single gear shift time is t; the single gear shift time is controlled to be 8. The machine tool spindle gearbox shifting mechanism according to claim 7, characterized in that: The single shift time t is between 0.4 seconds and 0.6 seconds.

9. A machine tool spindle gearbox shift control method, characterized in that: It comprises a spindle motor and a machine tool spindle gearbox shift mechanism as claimed in any one of claims 3 to 8, wherein the spindle motor comprises a converter, a frequency converter and a speed controller; The specific steps are as follows: (1) The spindle motor reduces the spindle speed to zero and keeps the controller on the converter enabled; (2) Inputting preset left and right yaw signals to the frequency converter and speed controller; (3) The driving mechanism (1) is energized, and the shift fork rod (2) starts to move to shift gears; (4) determining whether the shift fork lever (2) has moved to the corresponding gear position. If the shift fork lever (2) has moved to the corresponding gear position, the contact piece (3) will contact the corresponding gear position switch and send a signal to confirm that the gear shift is completed; (5) The left and right yaw signals of the frequency converter and speed controller on the spindle motor are turned off; (6) Driving mechanism (1) is closed; (7) The gear shifting action is completed; (8) The spindle motor starts to rotate; (9) If it is determined in step (4) that the shift fork lever (2) has not moved to the corresponding gear position, the shift fork lever (2) is returned to the initial position, and it is determined whether the shift fork lever (2) has been returned more than five times. If not, step (3) is repeated; (10) If the number of times the shift fork rod (2) is retracted in step (9) exceeds five times, the shift failure is confirmed and the power supply of the spindle motor is disconnected; (11) Check the gear shift mechanism for faults.

10. A machine tool spindle gearbox shift control method according to claim 9, characterized in that: The period of the spindle yaw is T, and the shift time used in one direction is t; N is a positive integer.

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