Workpiece clamping method, clamping device and machine tool

Abstract

The invention relates to the technical field of workpiece clamping, and provides a workpiece clamping method, a workpiece clamping device and a machine tool. A first encoder is arranged at the driving motor and is suitable for monitoring the number of turns of rotation of the driving motor; a second encoder is arranged at the machine tool spindle and is suitable for monitoring the number of rotation turns of the machine tool spindle; and feeding back the rotating circle value of the driving motor and the rotating circle value of the machine tool spindle to a controller so as to control the rotating states of the driving motor and the machine tool spindle according to the rotating circle values of the driving motor and the machine tool spindle. According to the workpiece clamping method provided by the invention, the driving motor is rigidly and directly connected with the pull rod, the first encoder is arranged at the driving motor, and the second encoder is arranged at the machine tool spindle, so that the debugging difficulty of workpiece clamping is reduced, and the monitoring precision of the workpiece clamping state can be improved; and the clamping and loosening actions of the workpiece are controlled more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of workpiece clamping, and in particular to a workpiece clamping method, a clamping device and a machine tool. Background Art

[0002] When machining a workpiece, it is usually necessary to clamp the workpiece. Generally, the workpiece is fixed on the machine tool by a chuck, and rotated at high speed driven by the motor. The tool is controlled to carve on the surface of the workpiece to achieve "cutting" to complete the processing. The chuck is a mechanical device used to clamp the workpiece on the machine tool. The radial movement of the movable jaws evenly distributed on the chuck body is used to clamp and position the workpiece. The chuck generally consists of three parts: the chuck body, the movable jaws, and the jaw drive motor assembly.

[0003] In the motor direct-connected servo clamping system, a single encoder is generally used to monitor the state of the motor, such as the number of motor rotations or torque parameters, so as to achieve real-time monitoring and adjustment of the clamping condition of the workpiece. For example, the corresponding encoder monitors the number of motor rotations to ensure whether the workpiece is clamped. Alternatively, in the dual-clutch structure servo clamping system, multiple external sensors are set to cooperate with the magnetic ring on the rotating force transmitter to achieve axial displacement positioning.

[0004] However, in the related workpiece clamping technology, the clamping system requires many parts and is difficult to install and debug. In addition, the motor is far away from the machine tool spindle, and the monitoring accuracy of the workpiece clamping state is low, making it difficult to accurately control the clamping and loosening 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 the workpiece is clamped, the difficulty of debugging can be reduced, the monitoring accuracy of the clamping state of the workpiece can be improved, and the precise control of the clamping and releasing actions of the workpiece 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] In order to achieve the purpose of the present invention, the present invention provides a workpiece clamping method, comprising the following steps:

[0009] Directly connect the drive motor and the tie rod rigidly;

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

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

[0012] The rotation circle value of the driving motor and the rotation circle value of the machine tool spindle are fed back to the controller to control the rotation state of the driving motor and the machine tool spindle according to the rotation circle values ​​of the two.

[0013] Preferably, in the step of providing a first encoder at the drive motor, which is suitable for monitoring the number of rotations of the drive motor,

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

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

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

[0017] Preferably, when the machine tool is waiting for material or loading material, 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, when the machine tool completes loading, the workpiece is placed in a clamped state, the machine tool spindle does not move, 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 according to the number of revolutions of the drive motor monitored by the first encoder and the number of revolutions of the machine tool spindle monitored by the second encoder, so as to release the workpiece.

[0021] The second aspect of the present invention further provides a clamping device, which is applied to the clamping device according to the above-mentioned workpiece clamping method, and the clamping device comprises:

[0022] A driving motor is rigidly directly connected to the pull rod;

[0023] A first encoder, provided on the drive motor, adapted to monitor the number of rotations of the drive motor;

[0024] The second encoder is arranged on the machine tool spindle and is suitable for monitoring the number of rotations of the machine tool spindle.

[0025] Preferably, the clamping device further comprises:

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

[0027] A reducer connected to the electric pull rod input shaft;

[0028] A screw rod connected to the reducer;

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

[0030] The third aspect of the present invention further provides a machine tool, which includes the above-mentioned clamping device and a machine tool body.

[0031] The clamping device is arranged 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 debugging the workpiece clamping by directly connecting the driving motor and the pull rod rigidly, and arranging a first encoder at the driving motor, and arranging a second encoder at the machine tool spindle, and can improve the monitoring accuracy of the clamping state of the workpiece, so that the clamping and releasing action control of the workpiece is more precise.

[0033] The clamping device provided by the present invention, because it is manufactured according to the above-mentioned workpiece clamping method, must have all the advantages of the method. That is, the clamping device can also reduce the difficulty of debugging the workpiece clamping, and can improve the monitoring accuracy of the workpiece clamping state, so that the clamping and loosening action control of the workpiece is more accurate.

[0034] The machine tool provided by the present invention, since it includes the above-mentioned clamping device, necessarily has all the advantages of the clamping device. That is, the machine tool can also reduce the difficulty of debugging the workpiece clamping, and can improve the monitoring accuracy of the workpiece clamping state, so that the clamping and loosening action control of the workpiece is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other purposes, features and advantages of the present invention will become more apparent through a more specific description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals indicate the same parts in all the accompanying drawings, and the drawings are not deliberately scaled to the actual size, but the focus is on illustrating the subject matter of the present application.

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

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

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

[0039] In the figure:

[0040] 1. Machine tool spindle; 2. Main housing;

[0041] 100. Driving motor;

[0042] 200, pull rod;

[0043] 300. a first encoder;

[0044] 400. second encoder;

[0045] 500, electric tie rod input shaft;

[0046] 600, reducer;

[0047] 700, screw;

[0048] 800, Screw nut. DETAILED DESCRIPTION

[0049] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings.

[0050] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to another element and integrated therewith, or there may be an intermediate element at the same time. The terms "installed", "one end", "the other end" and similar expressions used herein are for illustrative purposes only.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which they pertain. The terms used in the specification herein are intended only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0052] Combine the following Figures 1 to 3 It should be understood that the following description is only an illustrative embodiment of the present invention and does not constitute any limitation to the present invention.

[0053] Combination Figures 1 to 3 An embodiment of the present invention provides a method for clamping a workpiece, the method comprising the following steps:

[0054] Step 1: directly connect the drive motor 100 and the pull rod 200 rigidly; this can directly reduce the coupling components between the drive motor 100 and the pull rod 200 (for example, reduce the electromagnetic clutch, etc.), making the debugging difficulty when clamping the workpiece lower.

[0055] Step 2: A first encoder 300 is provided at the driving motor 100 to monitor the number of rotations of the driving motor 100 ; at this time, the number of rotations of the driving motor 100 can be recorded as A1.

[0056] Step 3: Set the second encoder 400 at the part fixedly connected to the machine tool spindle 1. For example, directly set the second encoder 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 set 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.

[0057] The rotation circle value A1 of the driving motor 100 and the rotation circle value B1 of the machine tool spindle 1 are fed back to the controller, and the controller can control the rotation state of the driving motor 100 and the machine tool spindle 1 according to the rotation circle values ​​of the two; that is, the controller can control the driving motor 100 to rotate forward, reverse or stop according to the rotation circle value A1 of the driving motor 100, and the controller can also control the machine tool spindle 1 to rotate forward, reverse or stop according to the rotation circle value B1 of the machine tool spindle 1. This makes the clamping or loosening control of the workpiece more precise, ensuring that the workpiece is clamped more firmly and does not loosen during processing, and the workpiece can be completely loosened after the processing is completed.

[0058] It can be understood that the clamping method for a workpiece provided in an embodiment of the present invention reduces the difficulty of debugging the workpiece clamping by directly connecting the drive motor 100 and the pull rod 200 with rigidity, and disposing a first encoder 300 at the drive motor 100, and disposing a second encoder 400 at the machine tool spindle 1, thereby improving the monitoring accuracy of the clamping state of the workpiece and making the clamping and releasing action control of the workpiece more precise.

[0059] Furthermore, in some embodiments of the present invention, in step 2, the workpiece clamping method further includes monitoring the rotation speed and angle parameters of the drive motor 100 to improve the monitoring accuracy of the state of the drive motor 100 .

[0060] In step three, the workpiece clamping method further includes monitoring the rotation angle position of the machine tool spindle 1 to improve the monitoring accuracy of the state of the machine tool spindle 1 .

[0061] In a specific embodiment of the present invention, when the machine tool is waiting for material or loading material, the workpiece is in a released state. At this time, the drive motor 100 and the machine tool spindle 1 are not running, the first encoder 300 only records the initial position value of the drive motor 100, and the second encoder 400 only records the initial position value of the machine tool spindle 1.

[0062] When the machine tool completes loading, the workpiece is in a clamped state, and the machine tool spindle 1 does not move. At this time, the second encoder 400 only records the initial position value of the machine tool spindle 1, and the drive motor 100 starts to actively rotate 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 recorded 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.

[0063] 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).

[0064] When the machine tool completes processing on 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 of the drive motor 100 monitored by the first encoder 300 (i.e., the sum of the above-mentioned A1 and A2 values) and the number of revolutions of the machine tool spindle 1 monitored by the second encoder 400 (i.e., the above-mentioned B1) to release the workpiece.

[0065] Moreover, since there are other connecting parts (such as lead screw, reducer, brake, etc.) between the first encoder 300 and the second encoder 400, the A2 value is usually inconsistent with the B2 value, and the A2 value is usually smaller than the number of turns recorded by the B2 value; therefore, when the machine tool completes the processing of the workpiece and the workpiece is released, the controller controls the number of turns R of the drive motor 100 to rotate in the opposite direction. When the drive motor 100 receives the number of turns R of release sent by the controller, the drive motor rotates in the opposite direction corresponding to the number of turns R to drive the workpiece to be released. R can be calculated according to the following formula:

[0066] R=A1+A2-B1+t, where t is a supplementary constant, which can be manually input during debugging to compensate for mechanical errors according to different clamping devices.

[0067] For example, when t is +0.5, the R value will automatically increase by 0.5 turns, that is, it will be loosened 0.5 turns more. When t is -0.5, the R value will automatically decrease by 0.5 turns, that is, it will be loosened 0.5 turns less.

[0068] Combination Figures 1 to 3According to the above-mentioned workpiece clamping method, an embodiment of the present invention further provides a clamping device, which is arranged 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.

[0069] The driving motor 100 and the pull rod 200 are directly connected by rigidity, which directly reduces the parts (such as electromagnetic clutch) for coupling the driving motor 100 and the pull rod 200 in the clamping device, thereby reducing the cost of accessories and making the structure of the clamping device simpler.

[0070] The first encoder 300 is disposed on the driving motor 100 and can monitor the number of rotations of the driving motor 100;

[0071] The second encoder 400 is disposed on the machine tool spindle 1 and can monitor the number of rotations of the machine tool spindle 1 .

[0072] It is understandable that the clamping device provided in the embodiment of the present invention, because it is manufactured according to the clamping method of the workpiece provided in the above embodiment, must have all the advantages of the method. That is, the clamping device can also reduce the difficulty of debugging the workpiece clamping, and can improve the monitoring accuracy of the clamping state of the workpiece, so that the clamping and loosening action control of the workpiece is more accurate.

[0073] Further, 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 screw 700, the screw nut 800 and the main housing 2.

[0074] The main housing 2 is used as the mounting body of the clamping device and can be fixedly mounted on the tail end of the machine tool spindle 1 and rotates with the machine tool spindle 1. The electric pull rod input shaft 500 is connected to the drive motor 100.

[0075] The reducer 600 is connected to the electric pull rod input shaft 500. The reducer 600 can reduce the rotation speed and amplify the torque. Usually, a 20 / 25 / 30 speed ratio is used, such as a 20 speed ratio.

[0076] The screw rod 700 is connected to the reducer 600. The screw rod 700 receives the speed and torque output by the reducer 600 to drive the screw nut 800 to move linearly. The lead thereof is usually 5 mm, 8 mm, 10 mm, etc., for example, the lead is 8 mm.

[0077] The screw nut 800 and the screw 700 form a screw transmission, which can convert the rotation drive of the drive motor 100 into an axial drive and transmit it to the pull rod 200 to achieve clamping of the workpiece.

[0078] Combination Figures 1 to 3An embodiment of the present invention further provides a machine tool, which includes the clamping device of the above embodiment and a machine tool body.

[0079] The clamping device is arranged on the machine tool body.

[0080] It is understandable that the machine tool provided by the embodiment of the present invention, since it includes the above-mentioned clamping device, must have all the advantages of the clamping device. That is, the machine tool can also reduce the difficulty of debugging the workpiece clamping, and can improve the monitoring accuracy of the workpiece clamping state, so that the clamping and loosening action control of the workpiece is more accurate.

[0081] In this specification, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0082] In the description of this specification, the description with reference to the terms "preferred embodiment", "further embodiment", "some embodiments", "other embodiments" or "specific example" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0083] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for clamping a workpiece, characterized in that: The following steps are involved: Directly connect the drive motor and the tie rod rigidly; A first encoder is arranged at the drive motor, which is suitable for monitoring the number of rotations of the drive motor; A second encoder is arranged at a component fixedly connected to the machine tool spindle, suitable for monitoring the number of rotations of the machine tool spindle; The rotation circle value of the driving motor and the rotation circle value of the machine tool spindle are fed back to the controller to control the rotation state of the driving motor and the machine tool spindle according to the rotation circle values ​​of the two.

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

3. The workpiece clamping method according to claim 1, characterized in that: In the step of providing a second encoder at the machine tool spindle, which is suitable for monitoring the number of rotations of the machine tool spindle, It also includes monitoring the rotational angular position of the machine tool spindle.

4. The workpiece clamping method according to claim 1, characterized in that: When the machine tool is waiting for material or loading material, 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.

5. The workpiece clamping method according to claim 4, characterized in that: When the machine tool completes loading, the workpiece is clamped, the machine tool spindle does not move, 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.

6. The workpiece clamping method according to 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 according to claim 6, characterized in that: When the machine tool completes processing of the workpiece, the controller controls the drive motor to rotate in the opposite direction according to the number of revolutions of the drive motor monitored by the first encoder and the number of revolutions of the machine tool spindle monitored by the second encoder, so as to release the workpiece.

8. A clamping device, characterized in that: The workpiece clamping method according to any one of claims 1 to 7 is applied to the clamping device, the clamping device is provided on a machine tool spindle, the machine tool spindle is provided with a pull rod, and the clamping device comprises: A driving motor is rigidly directly connected to the pull rod; A first encoder, provided on the drive motor, adapted to monitor the number of rotations of the drive motor; The second encoder is arranged on the machine tool spindle and is suitable for monitoring the number of rotations of the machine tool spindle.

9. The clamping device according to claim 8, characterized in that The clamping device also includes: An electric pull rod input shaft connected to the drive motor; A reducer connected to the electric pull rod input shaft; A screw rod connected to the reducer; The lead screw nut forms a lead screw transmission with the lead screw to convert the rotation drive of the drive motor into an axial drive and transmit it to the pull rod.

10. A machine tool, characterized in that: The clamping device and the machine tool body according to any one of claims 8 to 9 are included. The clamping device is arranged on the machine tool body.

Images