A numerically controlled turntable with gravity balancing function and control method thereof

Abstract

A CNC turntable with a gravity balancing function includes a support, a tray and a motor arranged on the support, wherein the motor is used to drive the tray to rotate on the support; it also includes a rotating shaft core, a left balance wheel, a right balance wheel and a drive assembly; one end of the rotating shaft core is relatively fixed to the tray, and the other end of the rotating shaft core is fixed to the drive assembly; the number of the left balance wheel and the right balance wheel is equal, and they are all rotatably connected to the rotating shaft core; the drive assembly is used to drive the left balance wheel and the right balance wheel to rotate synchronously in opposite directions, and to cooperate with the left balance wheel and the right balance wheel in a limited manner when the CNC turntable is in working condition. The present invention also provides a control method for applying the above-mentioned CNC turntable. Compared with the prior art, the CNC turntable of the present invention can balance the torque generated by the tray with workpieces of different masses.

Description

Technical Field

[0001] The present invention relates to the technical field of numerically controlled turntables, and in particular to a numerically controlled turntable with a gravity balancing function, and a control method for the numerically controlled turntable in an unbalanced state. Background Art

[0002] For workpieces with demanding machining requirements, three-axis machine tools are insufficient, so new CNC machine tools are often designed with four or more axes. The fourth and fifth axes of a typical machine tool are rotational axes, specifically the spindle or the workpiece. Rotating workpieces require a CNC turntable to support the workpiece.

[0003] If the CNC turntable is in a horizontal state (such as Figure 1 During machining, the CNC turntable rotates. Due to the gravity of the turntable and the workpiece itself, different torques are generated at different angles (maximum torque is generated when the turntable is vertical). The motor connected to the CNC turntable must generate opposing torque to maintain this state, significantly increasing the motor's load. This not only consumes energy but also reduces the motor's effective power and generates significant heat, reducing performance.

[0004] To this end, publication number CN105382624A provides a two-axis electric turntable mechanism with dual hydraulic cylinder counterweights and a method for compensating for overturning torque thereof, which reduces or reasonably compensates for the influence of the overturning torque of the turntable (i.e., the above-mentioned CNC turntable) through a mechanical balancing mechanism with dual hydraulic cylinder counterweights. Specifically, the mechanical balancing mechanism includes a balancing oil cylinder I1 and a balancing oil cylinder II2, wherein one end of the balancing oil cylinder I1 and the balancing oil cylinder II2 is fixed below the rotation axis A of the turntable of the U-shaped cradle 7 that generates the overturning torque through an end face ball bearing 3. When the U-shaped cradle 7 rotates around the rotation axis A, the cylinder bodies of the balancing oil cylinder I1 and the balancing oil cylinder II2 rotate around the cylinder earring 4 following the swing of the turntable, and the hydraulic control system 6 adjusts the pressure of the balancing oil cylinder I1 and the balancing oil cylinder II2, thereby compensating for the overturning torque of the turntable.

[0005] The compensation method used in the prior art, as described above, is actually a dynamic compensation method. The hydraulic control system 6 constantly adjusts the pressure of the balancing cylinder I1 and the balancing cylinder II2 according to the angle of the turntable. However, in high-reaction situations, synchronous control of the hydraulic system and the servo motor is essentially impossible to achieve. For example, in current high-efficiency machine tools, the balancing cylinders I1 and II2 will not keep up with the speed of the turntable's rotation, causing interference between the two. In addition, one end of the balancing cylinders I1 and II2 is connected below the rotation axis A of the turntable of the U-shaped cradle 7. When the required torque output of the cylinder is the maximum, the cylinder extends the longest and requires the most oil from the hydraulic system. As a result, the oil volume in the energy storage cylinder decreases, causing the oil pressure to drop and the cylinder force to decrease, resulting in unstable pressure during pressurization. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a numerically controlled turntable with a gravity balancing function.

[0007] To achieve the above objectives, the present invention discloses a CNC turntable with a gravity balancing function, comprising a support, a tray disposed on the support, and a motor, wherein the motor is used to drive the tray to rotate on the support;

[0008] It also includes a rotating shaft core, a left balance wheel, a right balance wheel and a drive assembly; one end of the rotating shaft core is fixed relatively to the tray, and the other end of the rotating shaft core is fixedly connected to the drive assembly; the number of the left balance wheels and the right balance wheels is equal, and they are all rotatably connected to the rotating shaft core; the drive assembly is used to drive the left balance wheel and the right balance wheel to rotate synchronously in opposite directions, and to cooperate with the left balance wheel and the right balance wheel in a limited manner when the CNC turntable is in working condition.

[0009] Preferably, the outlines of the left balance wheel and the right balance wheel are both circular, the outline of the left balance wheel is provided with a first transmission tooth, and the outline of the right balance wheel is provided with a second transmission tooth;

[0010] The driving assembly includes a left worm engaged with the first transmission teeth, a right worm engaged with the second transmission teeth, and a driving device for driving the left worm and the right worm to rotate.

[0011] Further preferably, the output end of the driving device is connected to the left worm, the left worm is provided with a driving gear, and the right worm is provided with a driven gear meshing with the driving gear.

[0012] Further preferably, the left balance wheel is provided with a left hammer, and the right balance wheel is provided with a right hammer.

[0013] Further preferably, the left hammer is provided on a side of the left balance wheel away from the right balance wheel, and the right hammer is provided on a side of the right balance wheel away from the left balance wheel.

[0014] Further preferably, the ratio between the diameter of the left balance wheel and its thickness is between 20:1 and 2:1; and / or

[0015] The ratio between the diameter of the right balance wheel and its thickness is between 20:1 and 2:1.

[0016] Further preferably, the left balance wheel is provided with a left hollow portion, and the right balance wheel is provided with a right hollow portion.

[0017] Further preferably, the left hollow portion is symmetrically arranged with respect to the center of the left hammer body, and the right hollow portion is symmetrically arranged with respect to the center of the right hammer body.

[0018] Preferably, a connecting rod is fixedly connected to the end of the rotating shaft core away from the tray, a bracket is provided at the end of the connecting rod away from the rotating shaft core, and the driving assembly is fixed to the bracket.

[0019] The invention also provides a control method for a numerically controlled turntable with a gravity balancing function.

[0020] A method for controlling a numerically controlled turntable with a gravity balancing function, the method using any one of the numerically controlled turntables described above, comprising the following steps:

[0021] Step 1: The motor drives the tray to rotate from a horizontal state to a vertical state;

[0022] Step 2: Detect the load of the motor in the vertical state;

[0023] Step 3: If the load of the motor exceeds the rated value, the drive assembly drives the left balance wheel and the right balance wheel to rotate, readjusts the position of the left balance wheel and the right balance wheel, and then returns to step 3; if the load of the motor is within the rated value, the adjustment is completed.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the CNC turntable of the present invention is provided with a rotating shaft core fixed to the pallet, and a left balance wheel and a right balance wheel are provided on the rotating shaft core, which can balance the torque generated by the pallet and the workpiece arranged on the pallet during the processing, thereby ensuring the stability of the pallet during the processing. In addition, no matter how fast the pallet rotates during the processing, the two balance hammers will not affect its processing, thus solving the problem of interference between the balance cylinder and the pallet caused by balancing the pallet (i.e., the turntable in the background technology) by the balance cylinder in the prior art. In the process of balancing the torque using two balance hammers, according to the mass of different workpieces or the change in the mass of the workpieces during the processing, the two balance hammers can be rotated to different angles and positions, thereby balancing the torque generated by workpieces of different masses. In addition, two balance hammers with opposite movement directions are provided, which can not only balance the torque generated by the pallet and the workpiece arranged on the pallet, but also balance the torque generated by the balance hammer itself at a special position. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the overall structure of a two-axis electric turntable mechanism with double hydraulic cylinder counterweights in the prior art CN105382624A;

[0026] Figure 2 for Figure 1 Side view of;

[0027] Figure 3 It is a three-dimensional schematic diagram of the numerical control turntable with gravity balancing function of the present invention in a horizontal state;

[0028] Figure 4 for Figure 3 Left view of the CNC turntable;

[0029] Figure 5 This is a three-dimensional schematic diagram of the numerically controlled turntable with gravity balancing function of the present invention after being rotated 45 degrees;

[0030] Figure 6 for Figure 5 Left view of the CNC turntable;

[0031] Figure 7 It is a three-dimensional schematic diagram of the numerical control turntable with gravity balancing function of the present invention in a vertical state;

[0032] Figure 8 for Figure 7 Left view of the CNC turntable;

[0033] Figure 9 This is a left view of a CNC turntable with only one balance wheel in a special position;

[0034] Figure 10This is the left side view of the CNC turntable for setting the two balance wheels in a special position;

[0035] Support 1;

[0036] Tray 2;

[0037] Rotating shaft core 3; connecting rod 31; bracket 32;

[0038] Left balance wheel 4; first transmission tooth 41; left hammer 42; left hollow portion 43;

[0039] Right balance wheel 5; second transmission tooth 51; right hammer 52; right hollow portion 53;

[0040] Driving assembly 6; left worm 61; driving gear 611; right worm 62; driven gear 621; driving device 63. DETAILED DESCRIPTION

[0041] In the description of the present invention, it should be understood that the terms "inside" and "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 therefore should not be understood as a limitation on the present invention.

[0042] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "fixed," and the like should be understood in a broad sense. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0043] Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without mutual contradiction.

[0044] Example 1

[0045] The following is combined with Figure 3-10 The technical solution of the present invention is further described.

[0046] A CNC turntable with gravity balance function, see Figure 3-Figure 8, including a support 1, a tray 2, a motor (not shown in the figure), a rotating shaft core 3, a left balance wheel 4, a right balance wheel 5 and a drive assembly 6. The tray 2 is rotatably connected to the support 1. Under working conditions or when adjusting the position of the weight, the motor drives the tray 2 to rotate on the support 1. One end of the rotating shaft core 3 is fixedly connected to the tray 2, and the other end of the rotating shaft core 3 is fixedly connected to the drive assembly 6, thereby supporting the drive assembly 6. The number of left balance wheels 4 and right balance wheels 5 is equal. In this embodiment, there is one left balance wheel 4 and one right balance wheel 5, and the structures and shapes of the two balance hammers are the same. They are both rotatably connected to the rotating shaft core 3. When the position of the weight needs to be adjusted, the spindle stops processing the workpiece on the CNC turntable, and the drive component 6 drives the left balance wheel 4 and the right balance wheel 5 to rotate synchronously in opposite directions, so that the two weights and the CNC turntable are in a balanced state; when the CNC turntable is in working condition, the drive component 6 cooperates with the left balance wheel 4 and the right balance wheel 5 to limit the position, so that the left balance wheel 4 and the right balance wheel 5 rotate synchronously with the pallet 2 to ensure that the pallet 2 can be in a balanced state in any state it rotates to.

[0047] The above CNC turntable is provided with a rotating shaft core 3 fixedly connected to the pallet 2, and a left balance wheel 4 and a right balance wheel 5 are provided on the rotating shaft core 3. This can balance the torque generated by the pallet 2 and the workpiece arranged on the pallet 2 during the processing, and ensure the stability of the pallet 2 during the processing. In addition, no matter how fast the pallet 2 rotates during the processing, the two balance hammers will not affect its processing, which solves the problem of interference between the balance cylinder and the pallet 2 caused by balancing the pallet 2 (i.e., the turntable in the background technology) by the balance cylinder in the prior art. In the process of balancing the torque, the two balance hammers can be rotated to different angles and positions according to the mass of different workpieces or the change in the mass of the workpieces during the processing, thereby balancing the torque generated by workpieces of different masses. In addition, two balance hammers with opposite movement directions are provided, which can not only balance the torque generated by the pallet 2 and the workpiece arranged on the pallet 2, but also balance the torque generated by the balance hammer itself at a special position. For example, in Figure 9 In the figure, tray 2 is on the left and in a vertical position. Only one counterweight is provided. At this time, there is a 45° central angle between the center of mass of the counterweight, the horizontal line, and the rotating axis 3. In this state, tray 2 and the center of mass are in equilibrium. If tray 2 is rotated to a horizontal position, there is a 45° central angle between the center of mass of the counterweight, the vertical line, and the rotating axis 3. The counterweight will generate a torque, and thus the equilibrium state cannot be achieved. Figure 10 , which is provided with two balancing hammers. When the tray 2 rotates to a horizontal state, the two balancing hammers can be symmetrical about the vertical line, thereby reaching a balanced state. That is, no matter which position the tray 2 rotates to, the two balancing hammers can reach a balanced state with the tray 2.

[0048] In this embodiment, see Figure 3-Figure 8 The end of the rotating shaft core 3 away from the tray 2 is fixedly connected to a connecting rod 31, and the end of the connecting rod 31 away from the rotating shaft core 3 is provided with a bracket 32. The outlines of the left balance wheel 4 and the right balance wheel 5 are both circular. The outline of the left balance wheel 4 is provided with a first transmission tooth 41, and the outline of the right balance wheel 5 is provided with a second transmission tooth 51. The driving assembly 6 includes a left worm 61, a right worm 62 and a driving device 63 connected to the bracket 32. The left worm 61 is engaged with the first transmission tooth 41, and the right worm 62 is engaged with the second transmission tooth 51. The driving device 63 is used to drive the left worm 61 and the right worm 62 to rotate. When the angle and position of the left balance wheel 4 and the right balance wheel 5 need to be adjusted, the driving device 63 drives the left worm 61 and the right worm 62 to rotate. Then, the left worm 61 drives the left balance wheel 4 to rotate, and the right worm 62 drives the right balance wheel 5 to rotate. When they rotate to the appropriate position, they stop rotating. The above-mentioned left worm 61 and right worm 62 can not only drive the left balance wheel 4 and the right balance wheel 5 to rotate; in addition, when the left balance wheel 4 and the right balance wheel 5 rotate to the appropriate position, the self-locking function of the worm gear is used to lock the left balance wheel 4 and the right balance wheel 5, so that the balance hammer cannot rotate; when the CNC turntable is in working condition, the worm gear can drive the balance hammer to move synchronously with the tray 2, thereby ensuring that the tray 2 and the balance hammer can be in a balanced state at any position.

[0049] It is understandable that in order to ensure that the left balance wheel 4 and the right balance wheel 5 are also in a balanced state, the left balance wheel 4 and the right balance wheel 5 have the same structure and size and are symmetrically distributed at all times, so that they can generate torques of equal magnitude and opposite directions.

[0050] In this embodiment, the driving device 63 is a motor. Figure 3-Figure 8 The output end of the driving device 63 is connected to the left worm 61. The left worm 61 is provided with a driving gear 611, and the right worm 62 is provided with a driven gear 621 that meshes with the driving gear 611. By connecting the driving gear 611 and the driven gear 621, when the driving device 63 drives the left worm 61 to rotate, the left worm 61 can synchronously drive the right worm 62 to rotate in the opposite direction, thereby driving the left balance wheel 4 and the right balance wheel 5 to move synchronously in the opposite direction, resulting in a simple structure.

[0051] In this embodiment, see Figure 3-Figure 8The left balance wheel 4 is provided with a left hammer 42 and a left hollow portion 43, both of which are 180-degree fan-shaped and centrally symmetrically arranged. The right balance wheel 5 is provided with a right hammer 52 and a right hollow portion 53, both of which are 180-degree fan-shaped and centrally symmetrically arranged. The masses of the left and right hammers 42 and 52 are equal. The above arrangement of the left hammer 42 on the left balance wheel 4 and the left hollow portion 43 at another centrally symmetrical position on the left balance wheel 4, and the same arrangement on the right balance wheel 5, not only reduces the mass of the left and right balance wheels 4 and 5, but also helps reduce their impact on the rotating shaft core 3, ensuring the rigidity of the rotating shaft core 3, thereby improving the balancing effect between the two balance wheels and the tray 2. Furthermore, the mass distribution of the two balance wheels is more even, further enhancing the balancing effect.

[0052] In this embodiment, the ratio between the diameter of the left balance wheel 4 and its thickness is between 20:1 and 2:1, and the ratio between the diameter of the right balance wheel 5 and its thickness is between 20:1 and 2:1. In practice, the ratio between the diameter of the left balance wheel 4 and its thickness is equal to the ratio between the diameter of the right balance wheel 5 and its thickness. In this way, the quality of the left balance wheel 4 and the right balance wheel 5 and their balancing effect can be guaranteed, while the thickness of the left balance wheel 4 and the right balance wheel 5 can be fully reduced, which is conducive to shortening the length of the rotating shaft core 3 and ensuring the rigidity of the rotating shaft core, thereby further improving the balancing effect between the two balance wheels and the tray 2.

[0053] In this embodiment, see Figure 3-Figure 8 The left hammer 42 is provided on the side of the left balance wheel 4 away from the right balance wheel 5, and the right hammer 52 is provided on the side of the right balance wheel 5 away from the left balance wheel 4. In this way, the gap between the left balance wheel 4 and the right balance wheel 5 can be reduced, and the assembly of the left balance wheel 4 and the right balance wheel 5 is more compact. In addition, the driving gear 611 and the driven gear 621 can use smaller gears, which reduces material costs.

[0054] Example 2

[0055] For example, when replacing workpieces of different masses or when significant changes occur between workpieces after machining, the angles and positions of the two balancing wheels on the CNC turntable need to be adjusted. Therefore, this embodiment provides a control method for the CNC turntable of Example 1, including the following steps:

[0056] Step 1: The spindle stops processing the workpiece to avoid interference caused by adjusting the angle and position of the two balance wheels during processing;

[0057] Step 2: The motor drives the tray 2 to rotate from a horizontal state to a vertical state;

[0058] Step 3: Detect the load of the motor in the vertical state;

[0059] Step 4: If the motor load exceeds the rated value, the drive assembly 6 drives the left balance wheel 4 and the right balance wheel 5 to rotate, and the positions of the left balance wheel 4 and the right balance wheel 5 are readjusted. Specifically, the drive device 63 drives the left worm 61 to rotate, and the left worm 61 drives the right worm 62 to rotate. The left worm 61 and the right worm 62 rotate, and then drive the left balance wheel 4 and the right balance wheel 5 to rotate, thereby adjusting the positions of the left balance wheel 4 and the right balance wheel 5. After the positions of the left balance wheel 4 and the right balance wheel 5 are adjusted, step 3 is repeated;

[0060] If the load of the motor is within the rated value, the left balance wheel 4 and the right balance wheel 5 can be in a balanced state with the tray 2, and the adjustment is completed.

[0061] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A CNC turntable with a gravity balancing function, comprising a support, a tray mounted on the support, and a motor, wherein the motor is configured to drive the tray to rotate on the support, characterized in that: The system further comprises a rotating shaft core, a left balance wheel, a right balance wheel, and a drive assembly; one end of the rotating shaft core is fixed relative to the tray, and the other end of the rotating shaft core is fixedly connected to the drive assembly; the number of the left balance wheels and the right balance wheels is equal, and they are all rotatably connected to the rotating shaft core; the drive assembly is used to drive the left balance wheel and the right balance wheel to rotate synchronously and in opposite directions, and is limitedly engaged with the left balance wheel and the right balance wheel when the CNC turntable is in working condition; The left balance wheel and the right balance wheel both have circular outlines, the left balance wheel has a first transmission tooth on its outline, and the right balance wheel has a second transmission tooth on its outline; The driving assembly includes a left worm gear meshing with the first transmission teeth, a right worm gear meshing with the second transmission teeth, and a driving device for driving the left and right worm gears to rotate; The output end of the driving device is connected to the left worm, the left worm is provided with a driving gear, and the right worm is provided with a driven gear meshing with the driving gear; The left balance wheel is provided with a left hammer, and the right balance wheel is provided with a right hammer.

2. The CNC turntable with gravity balancing function according to claim 1, characterized in that: The left hammer is arranged on the side of the left balance wheel away from the right balance wheel, and the right hammer is arranged on the side of the right balance wheel away from the left balance wheel.

3. The CNC turntable with gravity balancing function according to claim 1, characterized in that: The ratio between the diameter and thickness of the left balance wheel is between 20:1 and 2:1; and / or The ratio between the diameter of the right balance wheel and its thickness is between 20:1 and 2:

1.

4. The CNC turntable with gravity balancing function according to claim 1, characterized in that: The left balance wheel is provided with a left hollow portion, and the right balance wheel is provided with a right hollow portion.

5. The CNC turntable with gravity balancing function according to claim 4, characterized in that: The left hollow portion is symmetrically arranged with respect to the center of the left hammer body, and the right hollow portion is symmetrically arranged with respect to the center of the right hammer body.

6. The CNC turntable with gravity balancing function according to claim 1, characterized in that: The end of the rotating shaft core away from the tray is fixedly connected with a connecting rod, the end of the connecting rod away from the rotating shaft core is provided with a bracket, and the driving component is fixedly connected to the bracket.

7. A control method for a CNC turntable with a gravity balancing function, characterized in that: The control method applies the CNC turntable according to any one of claims 1 to 6, comprising the following steps: Step 1: The motor drives the tray to rotate from a horizontal state to a vertical state; Step 2: Detect the load of the motor in the vertical state; Step 3: If the load of the motor exceeds the rated value, the drive assembly drives the left balance wheel and the right balance wheel to rotate, readjusts the position of the left balance wheel and the right balance wheel, and then returns to step 3; if the load of the motor is within the rated value, the adjustment is completed.

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