Method for clamping workpiece, clamping device, and machine tool

Abstract

A method for clamping a workpiece, comprising: rigidly directly connecting a drive electric motor (100) to a drawbar (200); providing at the drive electric motor a first encoder (300) adapted to monitor the number of revolutions of the drive electric motor; providing at a machine tool spindle (1) a second encoder (400) adapted to monitor the number of revolutions of the machine tool spindle; and feeding back values of the number of revolutions of the drive electric motor and the number of revolutions of the machine tool spindle to a controller, so as to control the rotation states of the drive electric motor and the machine tool spindle on the basis of the values of the number of revolutions of the drive electric motor and the number of revolutions of the machine tool spindle. By rigidly directly connecting the drive electric motor to the drawbar and providing the first encoder at the drive electric motor and the second encoder at the machine tool spindle, the method for clamping a workpiece reduces the debugging difficulty of workpiece clamping and can improve the monitoring precision of the clamping state of the workpiece, thereby enabling more precise control of workpiece clamping and releasing actions. Further provided are a clamping device and a machine tool.

Description

Workpiece clamping methods, clamping devices and machine tools Technical Field

[0001] This invention relates to the field of workpiece clamping technology, and more specifically to a workpiece clamping method, clamping device, and machine tool. Background Technology

[0002] When machining workpieces, they typically need to be clamped. Generally, the workpiece is fixed to the machine tool by a chuck and rotates at high speed driven by a motor. The cutting tool is controlled to carve on the workpiece surface, thus achieving the "tool feed" and completing the machining process. The chuck is a mechanical device on a machine tool used to clamp the workpiece. It utilizes the radial movement of movable jaws evenly distributed on the chuck body to clamp and position the workpiece. A chuck generally consists of three parts: the chuck body, the movable jaws, and the jaw drive motor assembly.

[0003] In direct-drive servo clamping systems, a single encoder is typically used to monitor the motor's status, such as the number of revolutions or torque, to enable real-time monitoring and adjustment of the workpiece clamping. For example, the encoder monitors the number of motor revolutions to ensure the workpiece is clamped. Alternatively, in dual-clutch servo clamping systems, multiple external sensors are used in conjunction with a magnetic ring on the rotary actuator to achieve axial displacement positioning.

[0004] However, in related workpiece clamping technologies, the clamping system requires many parts, is difficult to install and debug, and the motor is far from the machine tool spindle, resulting in low accuracy in monitoring the workpiece clamping status, making it difficult to accurately control the clamping and releasing actions of the workpiece. Summary of the Invention

[0005] In view of the above-mentioned defects in the prior art, the present invention provides a workpiece clamping method to solve at least one of the above-mentioned technical defects in the prior art, so that when clamping the workpiece, the difficulty of debugging can be reduced, the monitoring accuracy of the workpiece clamping state can be improved, and the precise control of the workpiece clamping and releasing actions can be improved.

[0006] A second aspect of the present invention provides a clamping device.

[0007] A third aspect of the present invention provides a machine tool.

[0008] To achieve the objective of this invention, a workpiece clamping method is provided, comprising the following steps:

[0009] The drive motor is rigidly and directly connected to the tie rod;

[0010] A first encoder is installed at the drive motor, which is suitable for monitoring the number of rotations of the drive motor;

[0011] A second encoder is installed at a component that is fixedly connected to the machine tool spindle, which is suitable for monitoring the number of rotations of the machine tool spindle;

[0012] The rotational speed values ​​of the drive motor and the machine tool spindle are fed back to the controller to control the rotational state of the drive motor and the machine tool spindle based on these values.

[0013] Preferably, in the step of installing a first encoder at the drive motor to monitor the number of rotations of the drive motor,

[0014] It also includes monitoring the speed and angle parameters of the drive motor.

[0015] Preferably, in the step of installing a second encoder at the machine tool spindle to monitor the number of rotations of the machine tool spindle,

[0016] It also includes monitoring the rotational angle position of the machine tool spindle.

[0017] Preferably, when the machine tool is waiting for or loading materials, the workpiece is in a released state, the first encoder only records the initial position value of the drive motor, and the second encoder only records the initial position value of the machine tool spindle.

[0018] Preferably, after the machine tool completes the loading, the workpiece is clamped, the machine tool spindle remains stationary, the second encoder only records the initial position value of the machine tool spindle, and the first encoder records the number of rotations of the drive motor.

[0019] Preferably, when the machine tool processes the workpiece, the machine tool spindle rotates, the second encoder records the number of rotations of the machine tool spindle, and the first encoder continues to record the number of rotations of the drive motor.

[0020] Preferably, after the machine tool completes processing of the workpiece, the controller controls the drive motor to rotate in the opposite direction based on the number of revolutions the drive motor has rotated as detected by the first encoder and the number of revolutions the machine tool spindle has rotated as detected by the second encoder, so that the workpiece is released.

[0021] A second aspect of the present invention also provides a clamping device, which is applied according to the above-described workpiece clamping method, the clamping device comprising:

[0022] The drive motor is rigidly and directly connected to the pull rod.

[0023] A first encoder is disposed on the drive motor and is adapted to monitor the number of rotations of the drive motor;

[0024] A second encoder is located on the machine tool spindle and is adapted to monitor the number of rotations of the machine tool spindle.

[0025] Preferably, the clamping device further includes:

[0026] The electric pull rod input shaft is connected to the drive motor;

[0027] The speed reducer is connected to the input shaft of the electric pull rod;

[0028] The lead screw is connected to the reducer;

[0029] The lead screw nut, together with the lead screw, forms a lead screw drive to convert the rotational drive of the drive motor into axial drive and transmit it to the pull rod.

[0030] A third aspect of the present invention also provides a machine tool, which includes the above-described clamping device and machine tool body.

[0031] The clamping device is located on the machine tool body.

[0032] The beneficial effects of the present invention are as follows: The workpiece clamping method provided by the present invention reduces the difficulty of workpiece clamping debugging by rigidly connecting the drive motor and the pull rod, setting a first encoder at the drive motor and a second encoder at the machine tool spindle, and can improve the monitoring accuracy of the workpiece clamping state, making the clamping and releasing action control of the workpiece more precise.

[0033] The clamping device provided by this invention, being manufactured based on the aforementioned workpiece clamping method, inevitably possesses all the advantages of that method. That is, this clamping device can also reduce the difficulty of adjusting workpiece clamping, and can improve the monitoring accuracy of the workpiece clamping state, making the clamping and releasing actions of the workpiece more precise.

[0034] The machine tool provided by this invention, by including the aforementioned clamping device, inevitably possesses all the advantages of that clamping device. That is, the machine tool can also reduce the difficulty of adjusting workpiece clamping, and can improve the monitoring accuracy of the workpiece clamping state, making the clamping and releasing actions of the workpiece more precise. Attached Figure Description

[0035] The above and other objects, features, and advantages of the present invention will become clearer through a more detailed description of the preferred embodiments illustrated in the accompanying drawings. The same reference numerals denote the same parts throughout the drawings, and the drawings are not intentionally drawn to scale with actual dimensions; the focus is on illustrating the gist of this application.

[0036] Figure 1 is a block diagram of a workpiece clamping method provided in an embodiment of the present invention;

[0037] Figure 2 is a schematic diagram of the clamping device provided in an embodiment of the present invention;

[0038] Figure 3 is a schematic diagram of the connection relationship between the first encoder, the second encoder and the clamping device provided in an embodiment of the present invention.

[0039] In the diagram: 1. Machine tool spindle; 2. Main housing; 100. Drive motor; 200. Tie rod; 300. First encoder; 400. Second encoder; 500. Electric tie rod input shaft; 600. Reducer; 700. Lead screw; 800. Lead screw nut. Detailed Implementation

[0040] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings.

[0041] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to and integrated with the other component, or there may be an intervening component present. The terms "mounted," "one end," "the other end," and similar expressions used in this document are for illustrative purposes only.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this applies. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0043] The embodiments of the present invention will now be described with reference to Figures 1 to 3. It should be understood that the following description is merely an illustrative embodiment of the present invention and does not constitute any limitation on the present invention.

[0044] Referring to Figures 1 to 3, this embodiment of the invention provides a workpiece clamping method, which includes the following steps:

[0045] Step 1: Rigidly connect the drive motor 100 and the pull rod 200 directly; this can directly reduce the number of components that couple the drive motor 100 and the pull rod 200 (e.g., reduce the electromagnetic clutch, etc.), making the adjustment when clamping the workpiece easier.

[0046] Step 2: Set a first encoder 300 at the drive motor 100 to monitor the number of rotations of the drive motor 100; at this time, the number of rotations of the drive motor 100 can be recorded as A1.

[0047] Step 3: Install a second encoder 400 at the component fixedly connected to the machine tool spindle 1. For example, the second encoder can be installed directly on the machine tool spindle 1 to monitor the number of rotations of the machine tool spindle 1; at this time, the number of rotations of the machine tool spindle 1 can be recorded as B1. Of course, the second encoder 400 can also be installed on the main housing 2, because the main housing 2 can rotate synchronously with the machine tool spindle 1, and the relevant number of rotations can also be monitored on the main housing 2.

[0048] The rotation count A1 of the drive motor 100 and the rotation count B1 of the machine tool spindle 1 are fed back to the controller. The controller can control the rotation state of the drive motor 100 and the machine tool spindle 1 based on these two rotation counts. In other words, the controller can control the drive motor 100 to rotate forward, reverse, or stop based on the rotation count A1, and the controller can also control the machine tool spindle 1 to rotate forward, reverse, or stop based on the rotation count B1. This makes the clamping and releasing control of the workpiece more precise, ensuring that the workpiece is clamped more firmly and does not loosen during processing, and can be completely released after processing is completed.

[0049] It is understood that the workpiece clamping method provided in the embodiments of the present invention reduces the difficulty of workpiece clamping debugging by rigidly connecting the drive motor 100 and the pull rod 200, setting a first encoder 300 at the drive motor 100 and a second encoder 400 at the machine tool spindle 1, and can improve the monitoring accuracy of the workpiece clamping state, making the clamping and releasing action control of the workpiece more precise.

[0050] Furthermore, in some embodiments of the present invention, in step two, the workpiece clamping method further includes monitoring the rotational speed and angle parameters of the drive motor 100 to improve the monitoring accuracy of the state of the drive motor 100.

[0051] In step three, the workpiece clamping method also includes monitoring the rotation angle position of the machine tool spindle 1 to improve the monitoring accuracy of the machine tool spindle 1 status.

[0052] In a specific embodiment of the present invention, when the machine tool is waiting for or loading material, the workpiece is in a released state. At this time, neither the drive motor 100 nor the machine tool spindle 1 is running. The first encoder 300 only records the initial position value of the drive motor 100, while the second encoder 400 only records the initial position value of the machine tool spindle 1.

[0053] After the machine tool completes the loading, the workpiece is clamped and the machine tool spindle 1 remains stationary. At this time, the second encoder 400 only records the initial position value of the machine tool spindle 1, while the drive motor 100 starts to rotate actively to drive the pull rod 200 to clamp the workpiece. The first encoder 300 records the number of rotations of the drive motor 100 (which can be denoted as A1) and feeds A1 back to the controller. The controller controls the start and stop of the drive motor according to the value of A1.

[0054] When the machine tool processes the workpiece, the workpiece is clamped and the machine tool spindle 1 starts to rotate. At this time, the second encoder 400 records the number of rotations of the machine tool spindle 1 (which can be recorded as B1), and the first encoder 300 continues to record the number of rotations of the drive motor 100 (at this time, the number of rotations of the drive motor 100 is recorded as A2).

[0055] After the machine tool finishes processing the workpiece, the workpiece will be released. The controller controls the drive motor 100 to rotate in the opposite direction based on the number of revolutions that the drive motor 100 has rotated as monitored by the first encoder 300 (i.e., the sum of the values ​​A1 and A2 mentioned above) and the number of revolutions that the machine tool spindle 1 has rotated as monitored by the second encoder 400 (i.e., the value B1 mentioned above), so that the workpiece is released.

[0056] Furthermore, due to the presence of other connecting parts (e.g., lead screws, reducers, brakes, etc.) between the first encoder 300 and the second encoder 400, the values ​​A2 and B2 are usually inconsistent, and the number of revolutions recorded by A2 is typically smaller than that recorded by B2. Therefore, when the workpiece is released after the machine tool has finished machining it, the controller controls the drive motor 100 to rotate in the reverse direction by a number of revolutions R. When the drive motor 100 receives the release revolution number R from the controller, rotating in the reverse direction by the corresponding number of revolutions R can release the workpiece. R can be calculated using the following formula:

[0057] R = A1 + A2 - B1 + t, where t is a supplementary constant that can be manually input during debugging to compensate for mechanical errors, depending on the clamping device.

[0058] For example, when t is +0.5, the R value will automatically increase by 0.5 turns, meaning it will loosen by 0.5 turns more; when t is -0.5, the R value will automatically decrease by 0.5 turns, meaning it will loosen by 0.5 turns less.

[0059] Referring to Figures 1 to 3, according to the above-described workpiece clamping method, an embodiment of the present invention also provides a clamping device. The clamping device is disposed on a machine tool spindle 1, and the machine tool spindle 1 is provided with a pull rod 200. The clamping device includes a drive motor 100, a pull rod 200, a first encoder 300, and a second encoder 400.

[0060] In this design, the drive motor 100 and the pull rod 200 are rigidly directly connected; this directly reduces the number of parts (e.g., electromagnetic clutch) that couple the drive motor 100 and the pull rod 200 in the clamping device, thereby reducing component costs and simplifying the structure of the clamping device.

[0061] The first encoder 300 is installed in the drive motor 100 and can monitor the number of rotations of the drive motor 100;

[0062] The second encoder 400 is installed on the machine tool spindle 1 and can monitor the number of rotations of the machine tool spindle 1.

[0063] It is understood that the clamping device provided in the embodiments of the present invention, being manufactured according to the workpiece clamping method provided in the above embodiments, necessarily possesses all the advantages of that method. That is, the clamping device can also reduce the difficulty of adjusting workpiece clamping, and can improve the monitoring accuracy of the workpiece clamping state, making the clamping and releasing actions of the workpiece more precise.

[0064] Furthermore, in order to simplify the structure of the clamping device, in some embodiments of the present invention, the electric pull rod input shaft 500, the reducer 600, the lead screw 700, the lead screw nut 800, and the main housing 2 are included.

[0065] Among them, the main housing 2 serves as the mounting body of the clamping device and can be fixedly installed at the tail end of the machine tool spindle 1, rotating together with the machine tool spindle 1. The electric pull rod input shaft 500 is connected to the drive motor 100.

[0066] The reducer 600 is connected to the electric tie rod input shaft 500. The reducer 600 can reduce the speed and amplify the torque. It usually uses a constant speed ratio of 20 / 25 / 30, such as a speed ratio of 20.

[0067] The lead screw 700 is connected to the reducer 600. The lead screw 700 receives the speed and torque output by the reducer 600 to drive the lead screw nut 800 to move linearly. Its lead is usually available in 5mm, 8mm, 10mm, etc., for example, the lead is 8mm.

[0068] The lead screw nut 800 and the lead screw 700 form a lead screw drive, which can convert the rotational drive of the drive motor 100 into axial drive and transmit it to the tie rod 200 to achieve the clamping of the workpiece.

[0069] Referring to Figures 1 to 3, embodiments of the present invention also provide a machine tool, which includes the clamping device and machine tool body described in the above embodiments.

[0070] The clamping device is located on the machine tool body.

[0071] It is understood that the machine tool provided in the embodiments of the present invention, having included the aforementioned clamping device, necessarily possesses all the advantages of that clamping device. That is, the machine tool can also reduce the difficulty of adjusting workpiece clamping, and can improve the monitoring accuracy of the workpiece clamping state, making the clamping and releasing actions of the workpiece more precise.

[0072] In this specification, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0073] In the description of this specification, the use of terms such as "preferred embodiment," "another embodiment," "some embodiments," "other embodiments," or "specific example," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for clamping a workpiece, characterized in that, Includes the following steps: The drive motor is rigidly and directly connected to the tie rod; A first encoder is installed at the drive motor, which is suitable for monitoring the number of rotations of the drive motor; A second encoder is installed at a component that is fixedly connected to the machine tool spindle, which is suitable for monitoring the number of rotations of the machine tool spindle; The rotational speed values ​​of the drive motor and the machine tool spindle are fed back to the controller to control the rotational state of the drive motor and the machine tool spindle based on these values.

2. The workpiece clamping method as described in claim 1, characterized in that, In the step of installing a first encoder at the drive motor to monitor the number of rotations of the drive motor, It also includes monitoring the speed and angle parameters of the drive motor.

3. The workpiece clamping method as described in claim 1, characterized in that, In the step of installing a second encoder at the machine tool spindle to monitor the number of rotations of the machine tool spindle, It also includes monitoring the rotational angle position of the machine tool spindle.

4. The workpiece clamping method as described in claim 1, characterized in that, When the machine tool is waiting for or loading materials, the workpiece is released. The first encoder only records the initial position value of the drive motor, and the second encoder only records the initial position value of the machine tool spindle.

5. The workpiece clamping method as described in claim 4, characterized in that, After the machine tool completes the loading, the workpiece is clamped and the machine tool spindle remains stationary. The second encoder only records the initial position value of the machine tool spindle, while the first encoder records the number of rotations of the drive motor.

6. The workpiece clamping method as described in claim 5, characterized in that, When the machine tool processes the workpiece, the machine tool spindle rotates, the second encoder records the number of rotations of the machine tool spindle, and the first encoder continues to record the number of rotations of the drive motor.

7. The workpiece clamping method as described in claim 6, characterized in that, After the machine tool finishes processing the workpiece, the controller controls the drive motor to rotate in the opposite direction based on the number of revolutions the drive motor has rotated as detected by the first encoder and the number of revolutions the machine tool spindle has rotated as detected by the second encoder, so that the workpiece is released.

8. A clamping device, characterized in that, The workpiece clamping method according to any one of claims 1-7 is applied to the clamping device, the clamping device being disposed on a machine tool spindle, the machine tool spindle being provided with a drawbar, and the clamping device comprising: The drive motor is rigidly and directly connected to the pull rod. A first encoder is disposed on the drive motor and is adapted to monitor the number of rotations of the drive motor; A second encoder is located on the machine tool spindle and is adapted to monitor the number of rotations of the machine tool spindle.

9. The clamping device as described in claim 8, characterized in that, The clamping device further includes: The electric pull rod input shaft is connected to the drive motor; The speed reducer is connected to the input shaft of the electric pull rod; The lead screw is connected to the reducer; The lead screw nut, together with the lead screw, forms a lead screw drive to convert the rotational drive of the drive motor into axial drive and transmit it to the pull rod.

10. A machine tool, characterized in that, Includes the clamping device and machine tool body as described in any one of claims 8 to 9. The clamping device is located on the machine tool body.

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