JP5971758B2 - Spindle drive for machining center - Google Patents

Description

  The present invention relates to a spindle driving device for a machining center in which a spindle is driven to rotate by two drive motors.

  The machining center cuts the workpiece fixed on the table and processes it into a desired shape by rotating the spindle holding the cutting tool. The performance required for this machining center is mainly processing accuracy and cutting ability. The processing accuracy is shape accuracy and processing surface roughness, and the cutting capability is a cutting amount per unit time. In order to satisfy these performances, the spindle, which is the main unit of the machining center, requires high rotational accuracy and low vibration in terms of machining accuracy, and high rigidity, high speed rotation, and high output (high torque) in terms of cutting ability. Is required.

  The drive motor that rotationally drives the main shaft is generally an induction motor, and as shown in FIGS. 4 and 5, the output decreases as the rotation speed decreases from a certain number of rotations. Therefore, in order to use the output of the drive motor effectively, a reduction gear constituted by gears or the like is necessary. In recent years, the technology of motors has improved, and it has become possible to output to the low-speed rotation range. The main shaft and the drive motor can be directly coupled to each other without using a reduction gear, or the rotor and stator can be directly connected to the main shaft. Incorporating the system has become common. This contributes to higher rotation of the main shaft and is suitable for high-precision rotation because there is no vibration due to gear meshing.

  The applicant has two drive motors, a low-speed rotation drive motor that drives a reduction gear constituted by gears, and a high-speed rotation drive motor that is directly connected to the main shaft by a coupling. A spindle drive device for a machining center that switches the drive motor for rotation and rotationally drives the spindle has been developed (see Patent Document 1).

  The spindle drive device described in Patent Document 1 connects the output shaft of the reducer and the spindle with a shifter gear during rough machining that requires high torque in a low-speed rotation range, and provides high torque and heavy cutting by a low-speed rotation drive motor. Is possible. At this time, the high-speed rotation drive motor is rotated in response to the rotation of the main shaft. On the other hand, at the time of finishing, the shifter gear is removed from the main shaft, and the main shaft is directly driven to rotate by a high-speed rotation drive motor, so that high-precision rotation and high-speed rotation without vibration due to gear meshing can be obtained. At this time, the drive motor for low speed rotation is stopped. Even in the low-speed rotation range, the high-precision, low-vibration rotation necessary for finishing can be obtained by removing the shifter gear from the main shaft and directly driving the main shaft to rotate with a high-speed rotation drive motor.

Japanese Utility Model Publication No. 2-61541

  In recent years, there has been an increasing need to efficiently cut heat-resistant alloys (hard-to-cut materials) represented by parts related to aircraft engines, and a spindle drive device with higher torque than before is required. In response to this requirement, the current situation is responding by improving the performance of the motor, optimizing the speed reducer, and adopting a high output motor. However, since the high output motor causes an increase in the size of the motor, it is difficult to increase the output in the spindle drive device of a machining center with a limited installation space. In addition, the spindle unit is usually built in the column, and due to the increase in the size of the drive motor that accompanies higher output, it becomes necessary to secure a large space in the column, leading to a reduction in column rigidity. .

  Therefore, the present invention makes it possible to achieve high output by a compact drive mechanism, and it is possible to obtain optimum torque / output characteristics over the entire rotation range from the low speed rotation range to the high speed rotation range, and to achieve a high accuracy and low vibration spindle. A spindle driving device for a machining center capable of rotating is provided.

  In order to solve the above-described problems, the present invention provides a spindle driving device for a machining center that rotationally drives a spindle on which a tool is mounted. The first drive motor is disposed on the axis of the spindle and directly drives the spindle. And a different reduction ratio by controlling the rotational speeds of the second drive motor, which is arranged in parallel with the axis of the main shaft and drives the main shaft via a reduction gear mechanism, and the first drive motor and the second drive motor. A control device that simultaneously drives the first drive motor and the second drive motor, and the reduction gear mechanism includes a spindle gear fixed to the main shaft, A spindle driving device for a machining center, comprising: a shift gear that meshes with or disengages from the spindle gear by a shift mechanism.

  The spindle driving device for a machining center according to the present invention is characterized in that the shift gear meshes with the spindle gear during rough machining and separates from the spindle gear during finishing machining.

  Further, in the spindle driving device of the machining center according to the present invention, the first drive motor is a high-speed rotation drive motor having a large torque up to a high-speed rotation range, and the second drive motor is for low-speed rotation having a large torque in a low-speed rotation range. It is a drive motor.

  The present invention is a spindle drive device of a machining center that rotationally drives a spindle on which a tool is mounted, the first drive motor being arranged on the axis of the spindle and directly driving the spindle, and parallel to the axis of the spindle The output of each drive motor having a different reduction ratio is controlled by controlling the rotation speed of the second drive motor, which drives the main shaft via a reduction gear mechanism, and the first drive motor and the second drive motor. And a control device for simultaneously driving the first drive motor and the second drive motor, wherein the reduction gear mechanism is connected to the spindle gear by a spindle gear fixed to the main shaft and a shift mechanism. By having a configuration including a shift gear that meshes or disengages, the outputs of the drive motors with different reduction ratios are coordinated to drive the first drive motor and the second drive motor simultaneously. It is possible to achieve higher output, and higher output can be achieved with a compact drive mechanism than when driven by a single high-output motor, and the column in which the spindle unit is incorporated can also be reduced in size. There is an effect that high output can be achieved while maintaining the above.

  In the low-speed rotation range, by engaging the shift gear with the spindle gear, high torque is obtained by the second drive motor that drives the main shaft via the reduction gear mechanism, and the torque of the first drive motor is also added to increase the high torque.・ Heavy cutting is possible. On the other hand, in the high-speed rotation range, the main shaft and the reduction gear mechanism (parts other than the spindle gear) are separated by separating the shift gear from the spindle gear, and the first drive motor that directly drives the main shaft causes the gear to mesh. High-precision rotation and high-speed rotation without vibration can be obtained. As described above, the spindle driving device of the machining center according to the present invention can obtain the optimum torque / output characteristics over the entire rotation range from the low speed rotation range to the high speed rotation range, and also enables the spindle rotation with high accuracy and low vibration. There is an effect.

  Further, the spindle driving device of the machining center according to the present invention is configured such that the shift gear meshes with the spindle gear at the time of roughing and is detached from the spindle gear at the time of finishing, so that the second drive is performed at the time of roughing that requires high torque. The driving force of the motor is transmitted to the main shaft via the reduction gear mechanism, and the first driving motor that directly drives the main shaft and the output of the second driving motor are coordinated by the control device, thereby enabling high torque and heavy cutting. . On the other hand, at the time of finishing, the main shaft and the reduction gear mechanism (parts other than the spindle gear) are separated, and the main shaft is directly driven only by the first drive motor. High speed rotation is obtained. Therefore, the spindle drive device of the machining center according to the present invention has an effect of improving both high output (high torque) during rough machining and high rotational accuracy and low vibration during finishing.

  Further, in the spindle driving device of the machining center according to the present invention, the first drive motor is a high-speed rotation drive motor having a large torque up to a high-speed rotation range, and the second drive motor is for low-speed rotation having a large torque in a low-speed rotation range. By being a drive motor, a larger torque can be obtained during rough machining in a low-speed rotation region, and even a heat-resistant alloy (difficult-to-cut material) can be cut efficiently. Further, at the time of finishing processing, it becomes possible to rotate at a higher speed, and there is an effect that the processing accuracy and cutting ability can be improved by high-precision and high-speed rotation.

The block diagram which shows one Example of the spindle drive device of the machining center which concerns on this invention. The figure which shows the output characteristic of the spindle drive. The figure which shows the torque characteristic of the spindle drive. The figure which shows the torque / output characteristic of the conventional drive motor for low speed rotation. The figure which shows the torque / output characteristic of the conventional high-speed rotation drive motor.

Embodiments of the present invention will be described based on examples shown in the drawings.
A spindle driving device of a machining center according to the present invention rotates a spindle 1 on which a tool is mounted, is disposed on the axis of the spindle 1 and directly drives the spindle 1; The second drive motor 4 that is arranged in parallel with the axis of the main shaft 1 and drives the main shaft 1 via the reduction gear mechanism 6, and the rotational speeds of the first drive motor 2 and the second drive motor 4 are controlled. And a control device 10 that simultaneously drives the first drive motor 2 and the second drive motor 4 by coordinating the outputs of the drive motors 2 and 4 having different reduction ratios, and the reduction gear mechanism 6 includes: A spindle gear 8 fixed to the main shaft 1 and a shift gear 7 meshed with or disengaged from the spindle gear 8 by a shift mechanism are provided.

  FIG. 1 is a configuration diagram showing an embodiment of a spindle driving device of a machining center according to the present invention. In the embodiment shown in FIG. 1, a spindle (spindle shaft) 1 is rotatably supported on a spindle head (not shown) by a bearing 21 such as a ball bearing. A first drive motor 2 is directly connected to the rear end portion of the main shaft 1 via a coupling 3.

  A spindle gear 8 is fixed to the main shaft 1. The reduction gear mechanism 6 includes the spindle gear 8, a shift gear 7 that meshes with or disengages from the spindle gear 8 by a shift mechanism (not shown), and a reduction gear group that decelerates in three stages. The second drive motor 4 is connected to the reduction gear mechanism 6 via a coupling 5, and the rotation of the second drive motor 4 is decelerated (the torque is increased) via the reduction gear mechanism 6. 1 is transmitted. In the illustrated reduction gear mechanism 6, the rotation of the second drive motor 4 is reduced in three stages by a reduction gear group, but the number of gears and the reduction ratio are arbitrary.

  A reduction gear group constituting the reduction gear mechanism 6 is rotatably supported on a gear casing (not shown) by a bearing 22 such as a ball bearing. The shift gear 7 is rotatably supported on the gear casing by a bearing 23 such as a ball bearing, and is configured to move in the axial direction by the shift mechanism so as to mesh with or disengage from the spindle gear 8. As the shift mechanism, a solenoid or the like can be used in addition to a hydraulic cylinder or an air cylinder.

  In the embodiment, the first drive motor 2 is a high-speed rotation drive motor having a large torque up to a high-speed rotation region, and the second drive motor 4 is a low-speed rotation drive motor having a large torque in a low-speed rotation region. The driving force of the second drive motor 4 is further transmitted through the reduction gear mechanism 6 and transmitted to the main shaft 1.

  In FIG. 1, reference numeral 10 denotes a control device, which is connected to the first drive motor 2 and the second drive motor 4 via a signal line 11 and a power line 12. The signal line 11 transmits detection data such as rotational speed detected by the first drive motor 2 and the second drive motor 4 to the control device 10. The control device 10 compares the detection data such as the rotation speeds of the first drive motor 2 and the second drive motor 4 and controls the supply power so that the rotation speeds of the respective drive motors are appropriate. Power is supplied to the first drive motor 2 and the second drive motor 4 via the first drive motor 2 and the second drive motor 4.

  At the time of rough machining, as shown in FIG. 1, the shift gear 7 meshes with the spindle gear 8, and the control device 10 controls the rotational speeds of the first drive motor 2 and the second drive motor 4 to drive each drive with different reduction ratios. The motor outputs are coordinated to drive the first drive motor 2 and the second drive motor 4 simultaneously. Therefore, at the time of rough machining, as shown in FIGS. 2 and 3, the main shaft 1 is connected to the output (broken line in the figure) of the second drive motor 4 for low speed rotation that drives the main shaft 1 via the reduction gear mechanism 6. The output of the first drive motor 2 that is directly driven (the alternate long and short dash line in the figure) is added to obtain a high output and high torque driving force (solid line in the figure).

  At the time of finishing, the shift gear 7 is separated from the spindle gear 8 by the shift mechanism, so that the main shaft 1 and the reduction gear group of the reduction gear mechanism 6 are separated, and the main shaft 1 is directly only by the first drive motor 2 for high speed rotation. Since it is driven, high-precision rotation and high-speed rotation without vibration due to gear meshing can be obtained.

  As shown in FIGS. 4 and 5, the output of a general drive motor decreases as the rotation speed decreases from a certain rotation speed. The drive motor for high speed rotation shown in FIG. 5 has a constant output in the high speed rotation range (2000 rpm or more), but the torque in the low speed rotation range (2000 rpm or less) is thin, and the output decreases as the rotation speed decreases. On the other hand, the drive motor for low rotation shown in FIG. 4 has a large torque in the low speed rotation range (1000 rpm or less) and can obtain the maximum output at the rotation speed of 1000 rpm, but rapidly in the high speed rotation range (2000 rpm or more). The torque decreases and the output decreases as the rotation speed increases.

  In recent years, there has been a demand for a spindle drive device having a higher torque than conventional ones. However, when the torque of the drive motor is increased, the drive motor becomes larger, which makes it difficult to increase the speed. In addition, an increase in the size of the drive motor leads to an increase in cost and a reduction in column rigidity, resulting in a decrease in machining accuracy.

  As described above, the spindle driving device of the machining center according to the present invention controls the rotational speeds of the first drive motor 2 and the second drive motor 4 to coordinate the outputs of the respective drive motors with different reduction ratios. The mechanism makes it possible to dramatically increase the output, and the column in which the spindle unit is incorporated can be downsized even with a high output machine. That is, the spindle drive device of the machining center of the present invention can increase the output while maintaining the rigidity of the column, so that sufficient high torque and heavy cutting can be performed during rough machining, and high accuracy and low vibration can be achieved during finish machining. The main shaft can be rotated.

DESCRIPTION OF SYMBOLS 1 Main shaft 2 1st drive motor 3 Coupling 4 2nd drive motor 5 Coupling 6 Reduction gear mechanism 7 Shift gear 8 Spindle gear 10 Control device 11 Signal line 12 Power line 21,22,23 Bearing

Claims (2)

A spindle driving device of a machining center that rotationally drives a spindle on which a tool is mounted,
A first drive motor disposed on an axis of the main shaft and directly driving the main shaft via a coupling ;
A second drive motor disposed parallel to the axis of the main shaft and driving the main shaft via a reduction gear mechanism;
Detecting the rotation speeds of the first drive motor and the second drive motor, controlling the rotation speeds of the first drive motor and the second drive motor to coordinate the outputs of the respective drive motors with different reduction ratios; A controller that simultaneously drives the first drive motor and the second drive motor;
The reduction gear mechanism includes a spindle gear fixed to the main shaft, and a shift gear meshed with or disengaged from the spindle gear by a shift mechanism ,
A spindle driving device for a machining center in which the shift gear meshes with the spindle gear during rough machining and is detached from the spindle gear during finishing machining . The first drive motor is a high-speed rotation drive motor having a large torque up to a high-speed rotation range compared to the second drive motor, and the second drive motor is a low-speed rotation range compared to the first drive motor . 2. The spindle drive device for a machining center according to claim 1, wherein the spindle drive device is a low-speed rotation drive motor having a large torque.

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